CVE-2023-5176

CRITICALNVD 9.89.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2023-09-27. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3

Also known asEUVD-2023-57513 (ENISA EUVD) · GHSA-238m-xccf-m2f6 (GitHub Security Advisories)Source: ENISA EUVD

9.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.4%CVSS: 9.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Memory safety bugs present in Firefox 117, Firefox ESR 115.2, and Thunderbird 115.2. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 118, Firefox ESR < 115.3, and Thunderbird < 115.3.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
60
EG Risk 60/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation1.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
1.4%
EPSS %ILE
72nd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
1.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)3 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

September 27, 2023

Last Modified

June 17, 2026

Advisory Details (8)

Auto-updated Nov 1, 2026
Patch available.
Web pageMentions a patch (unverified)

[SECURITY] [DLA 3587-1] firefox-esr security update

https://lists.debian.org/debian-lts-announce/2023/09/msg00034.html
Web page

Security Vulnerabilities fixed in Thunderbird 115.3 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2023-43/
Web page

Security Vulnerabilities fixed in Firefox ESR 115.3 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2023-42/
Web page

Security Vulnerabilities fixed in Firefox 118 — Mozilla

https://www.mozilla.org/security/advisories/mfsa2023-41/
Web page

[SECURITY] [DSA 5513-1] thunderbird security update

https://www.debian.org/security/2023/dsa-5513
Web page

[SECURITY] [DSA 5506-1] firefox-esr security update

https://www.debian.org/security/2023/dsa-5506
Web pageMentions a patch (unverified)

[SECURITY] [DLA 3601-1] thunderbird security update

https://lists.debian.org/debian-lts-announce/2023/10/msg00015.html

Vendor Advisories for CVE-2023-5176(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(18)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntuxul-ext-lightning (1:115.3.1+build1-0ubuntu0.20.04.1) @ focal2026-11-12ubuntu
ubuntufirefox-mozsymbols (118.0.1+build1-0ubuntu0.20.04.1) @ focal2026-11-12ubuntu
redhatthunderbird-0:115.3.1-1.el7_92023-10-05redhat
redhatfirefox-0:115.3.1-1.el7_92023-10-05redhat
redhatthunderbird-0:115.3.1-1.el8_22023-10-04redhat
redhatfirefox-0:115.3.1-1.el8_42023-10-04redhat
redhatfirefox-0:115.3.1-1.el8_12023-10-04redhat
redhatfirefox-0:115.3.1-1.el8_22023-10-04redhat
redhatthunderbird-0:115.3.1-1.el9_02023-10-04redhat
redhatfirefox-0:115.3.1-1.el8_82023-10-04redhat
redhatthunderbird-0:115.3.1-1.el8_62023-10-04redhat
redhatfirefox-0:115.3.1-1.el9_02023-10-04redhat
redhatthunderbird-0:115.3.1-1.el8_82023-10-04redhat
redhatfirefox-0:115.3.1-1.el9_22023-10-04redhat
redhatfirefox-0:115.3.1-1.el8_62023-10-04redhat
redhatthunderbird-0:115.3.1-1.el9_22023-10-04redhat
redhatthunderbird-0:115.3.1-1.el8_12023-10-04redhat
redhatthunderbird-0:115.3.1-1.el8_42023-10-04redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(16 across 11 ecosystems)
Debian:10(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr102.1.0esr-1 ... 91.9.1esr-1~deb9u1 (219 versions)
  • every version up to 115.3.0esr-1~deb10u1: fixed in 115.3.0esr-1~deb10u1
—
thunderbird1:102.0.1-1 ... 1:91.9.0-1~deb9u1 (279 versions)
  • every version up to 1:115.3.1-1~deb10u1: fixed in 1:115.3.1-1~deb10u1
—
Debian:11(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr102.1.0esr-1 ... 91.9.1esr-1~deb9u1 (117 versions)
  • every version up to 115.3.0esr-1~deb11u1: fixed in 115.3.0esr-1~deb11u1
—
thunderbird1:102.0.1-1 ... 1:91.9.0-1~deb9u1 (156 versions)
  • every version up to 1:115.3.1-1~deb11u1: fixed in 1:115.3.1-1~deb11u1
—
Debian:12(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr102.11.0esr-1 ... 115.3.0esr-1~deb11u1 (24 versions)
  • every version up to 115.3.0esr-1~deb12u1: fixed in 115.3.0esr-1~deb12u1
—
thunderbird1:102.11.0-1 ... 1:115.3.1-1~deb11u1 (41 versions)
  • every version up to 1:115.3.1-1~deb12u1: fixed in 1:115.3.1-1~deb12u1
—
Debian:13(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr—
  • every version up to 115.3.0esr-1: fixed in 115.3.0esr-1
—
thunderbird—
  • every version up to 1:115.3.0-1: fixed in 1:115.3.0-1
—
Debian:14(2)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr—
  • every version up to 115.3.0esr-1: fixed in 115.3.0esr-1
—
thunderbird—
  • every version up to 1:115.3.0-1: fixed in 1:115.3.0-1
—
Alpine:v3.18(1)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr—
  • every version up to 115.3.0-r0: fixed in 115.3.0-r0
—
Alpine:v3.19(1)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr—
  • every version up to 115.3.0-r0: fixed in 115.3.0-r0
—
Alpine:v3.20(1)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr—
  • every version up to 115.3.0-r0: fixed in 115.3.0-r0
—
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr—
  • every version up to 115.3.0-r0: fixed in 115.3.0-r0
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr—
  • every version up to 115.3.0-r0: fixed in 115.3.0-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
firefox-esr—
  • every version up to 115.3.0-r0: fixed in 115.3.0-r0
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(18)

Data Freshness Timeline

(refreshed 21× in last 7d / 89× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 306 rows on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 206 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 08:27 UTCEchelonGraph re-scored
  2. 2026-11-13 08:27 UTCVendor advisory
  3. 2026-11-13 08:27 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  4. 2026-11-12 16:30 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  5. 2026-11-12 07:18 UTCEchelonGraph re-scored
  6. 2026-11-12 07:18 UTCVendor advisory
  7. 2026-11-12 07:18 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-11-11 16:34 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  9. 2026-11-11 06:10 UTCEchelonGraph re-scored
  10. 2026-11-11 06:10 UTCVendor advisory
  11. 2026-11-11 06:10 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  12. 2026-11-10 16:37 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  13. 2026-11-10 05:00 UTCEchelonGraph re-scored
  14. 2026-11-10 05:00 UTCVendor advisory
  15. 2026-11-10 05:00 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  16. 2026-11-09 16:30 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  17. 2026-11-09 03:53 UTCEchelonGraph re-scored
  18. 2026-11-09 03:53 UTCVendor advisory
  19. 2026-11-09 03:53 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  20. 2026-11-08 16:35 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  21. 2026-11-08 02:46 UTCEchelonGraph re-scored
  22. 2026-11-08 02:46 UTCVendor advisory
  23. 2026-11-08 02:46 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  24. 2026-11-07 16:35 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  25. 2026-11-07 01:38 UTCEchelonGraph re-scored
Show 75 more
  1. 2026-11-07 01:38 UTCVendor advisory
  2. 2026-11-07 01:38 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  3. 2026-11-06 16:31 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  4. 2026-11-06 00:31 UTCEchelonGraph re-scored
  5. 2026-11-06 00:31 UTCVendor advisory
  6. 2026-11-06 00:31 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  7. 2026-11-05 16:33 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  8. 2026-11-04 23:24 UTCEchelonGraph re-scored
  9. 2026-11-04 23:24 UTCVendor advisory
  10. 2026-11-04 23:24 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  11. 2026-11-04 18:55 UTCOSV refresh
  12. 2026-11-04 16:31 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  13. 2026-11-03 22:16 UTCEchelonGraph re-scored
  14. 2026-11-03 22:16 UTCVendor advisory
  15. 2026-11-03 22:16 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  16. 2026-11-03 16:41 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  17. 2026-11-02 21:02 UTCEchelonGraph re-scored
  18. 2026-11-02 21:02 UTCVendor advisory
  19. 2026-11-02 21:02 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  20. 2026-11-02 16:40 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  21. 2026-11-01 19:54 UTCEchelonGraph re-scored
  22. 2026-11-01 19:54 UTCVendor advisory
  23. 2026-11-01 19:54 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  24. 2026-11-01 16:31 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  25. 2026-10-31 18:47 UTCEchelonGraph re-scored
  26. 2026-10-31 18:47 UTCVendor advisory
  27. 2026-10-31 18:47 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  28. 2026-10-31 16:30 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  29. 2026-10-30 17:39 UTCEchelonGraph re-scored
  30. 2026-10-30 17:39 UTCVendor advisory
  31. 2026-10-30 17:39 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  32. 2026-10-30 16:31 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  33. 2026-10-29 16:32 UTCEchelonGraph re-scored
  34. 2026-10-29 16:32 UTCVendor advisory
  35. 2026-10-29 16:32 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  36. 2026-10-29 16:30 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  37. 2026-10-28 16:29 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  38. 2026-10-28 15:24 UTCEchelonGraph re-scored
  39. 2026-10-28 15:24 UTCVendor advisory
  40. 2026-10-28 15:24 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  41. 2026-10-27 16:29 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  42. 2026-10-27 14:17 UTCEchelonGraph re-scored
  43. 2026-10-27 14:17 UTCVendor advisory
  44. 2026-10-27 14:16 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  45. 2026-10-26 16:29 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  46. 2026-10-26 12:41 UTCVendor advisory
  47. 2026-10-26 12:41 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  48. 2026-10-25 17:29 UTCEchelonGraph re-scored
  49. 2026-10-25 16:30 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  50. 2026-10-25 11:28 UTCEchelonGraph re-scored
  51. 2026-10-25 11:28 UTCVendor advisory
  52. 2026-10-25 11:28 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  53. 2026-10-24 16:29 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  54. 2026-10-24 10:21 UTCEchelonGraph re-scored
  55. 2026-10-24 10:21 UTCVendor advisory
  56. 2026-10-24 10:21 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  57. 2026-10-23 16:29 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  58. 2026-10-23 09:13 UTCEchelonGraph re-scored
  59. 2026-10-23 09:13 UTCVendor advisory
  60. 2026-10-23 09:13 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  61. 2026-10-22 16:31 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  62. 2026-10-22 08:05 UTCEchelonGraph re-scored
  63. 2026-10-22 08:05 UTCVendor advisory
  64. 2026-10-22 08:05 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  65. 2026-10-21 16:29 UTCEPSS rescoreEPSS 1.4% · 72nd percentile
  66. 2026-10-21 06:54 UTCEchelonGraph re-scored
  67. 2026-10-21 06:54 UTCVendor advisory
  68. 2026-10-21 06:54 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  69. 2026-10-20 16:30 UTCEPSS rescoreEPSS 1.4% · 71st percentile
  70. 2026-10-20 05:46 UTCEchelonGraph re-scored
  71. 2026-10-20 05:46 UTCVendor advisory
  72. 2026-10-20 05:46 UTCGHSA enrichmentGHSA-238m-xccf-m2f6 · GitHub severity CRITICAL · GitHub CVSS 9.8
  73. 2026-10-19 16:29 UTCEPSS rescoreEPSS 1.4% · 71st percentile
  74. 2026-10-19 04:38 UTCEchelonGraph re-scored
  75. 2026-10-19 04:38 UTCVendor advisory

Frequently asked(5)

What is CVE-2023-5176?
CVE-2023-5176 is a critical-severity vulnerability; its CVE record was published on September 27, 2023. Memory safety bugs present in Firefox 117, Firefox ESR 115.2, and Thunderbird 115.2. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 118, Firefox ESR <…
When was the CVE record for CVE-2023-5176 published?
The CVE record for CVE-2023-5176 was published on September 27, 2023. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of June 17, 2026; the record at its source may have been updated since.
Is CVE-2023-5176 actively exploited?
CVE-2023-5176 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.4% probability of exploitation in the next 30 days (72nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2023-5176?
CVE-2023-5176 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2023-5176?
A fix for CVE-2023-5176 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2023-5176 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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