CVE-2026-76641

HIGHPre-NVD 7.57.5
EchelonGraph scoreMEDIUM confidence

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

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-08-20. The CNA's CVSS baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: the CNA's CVSS, EPSS, GitHub Security Advisory

Also known asEUVD-2026-63493 (ENISA EUVD) · GHSA-r6r4-8m79-7vvv (GitHub Security Advisories)Source: ENISA EUVD

7.5EG
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: 0.4%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory corruption by processing XML with external entity parsers created via XML_ExternalEntityParserCreate. A struct size mismatch between ELEMENT_TYPE members causes storeAtts to read the attIndex member past allocated memory boundaries, resulting in failure to normalize whitespace in non-CDATA attributes or a wild pointer dereference causing a segfault. This vulnerability was introduced by the fix for CVE-2026-66046.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
49
EG Risk 49/100

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)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.4% × 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 partial (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
0.4%
EPSS %ILE
29th
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 (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-07). 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: 14 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 partial (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)14 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 partial (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

August 20, 2026

Last Modified

November 8, 2026

Advisory Details (3)

Auto-updated Aug 20, 2026
Patch available. Sources: github_pr, github_commit.
Web page

Expat Out-of-Bounds Read via dtdCopy | Advisories | VulnCheck

https://www.vulncheck.com/advisories/expat-out-of-bounds-read-via-dtdcopy
GitHub commit

commit 98599f6dcc2b (libexpat/libexpat)

Fix landed in libexpat/libexpat commit 98599f6dcc2b — awaiting tagged release

https://github.com/libexpat/libexpat/commit/98599f6dcc2b460410881fe420f5f55d6bec63bf
GitHub pull request

[CVE-2026-76641] lib: Fix out-of-bounds read from hash table entries created by dtdCopy

Fix merged in libexpat/libexpat PR #1331 on 2026-08-20 — awaiting tagged release

https://github.com/libexpat/libexpat/pull/1331

Vendor Advisories for CVE-2026-76641(2)

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

Patch Availability(2)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibexpat1-dev (2.1.0-7ubuntu0.16.04.5+esm14) @ xenial2026-10-27ubuntu
redhatexpat-main-2.8.4-0.1.hum12026-09-08redhat

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

(4 across 4 ecosystems)
Alpine:v3.21(1)
PackageVulnerable rangeFix by version rangeDependents
expat—
  • every version up to 2.8.4-r0: fixed in 2.8.4-r0
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
expat—
  • every version up to 2.8.4-r0: fixed in 2.8.4-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
expat—
  • every version up to 2.8.4-r0: fixed in 2.8.4-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
expat—
  • every version up to 2.8.4-r0: fixed in 2.8.4-r0
—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 9× in last 7d / 40× 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 263 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 163 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  2. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  3. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  4. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  5. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  6. 2026-11-08 14:17 UTCEchelonGraph re-scored
  7. 2026-11-08 14:17 UTCVendor advisory
  8. 2026-11-08 14:17 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  9. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  10. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  11. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  12. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  13. 2026-11-03 23:42 UTCEchelonGraph re-scored
  14. 2026-11-03 23:42 UTCVendor advisory
  15. 2026-11-03 23:42 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  16. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  17. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  18. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  19. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  20. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  21. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  22. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  23. 2026-10-27 21:09 UTCEchelonGraph re-scored
  24. 2026-10-27 21:09 UTCVendor advisory
  25. 2026-10-27 21:09 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
Show 75 more
  1. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  2. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  3. 2026-10-26 10:26 UTCEchelonGraph re-scored
  4. 2026-10-26 10:26 UTCVendor advisory
  5. 2026-10-26 10:26 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  6. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  7. 2026-10-25 14:01 UTCEchelonGraph re-scored
  8. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  9. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  10. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  11. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  12. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  13. 2026-10-20 09:07 UTCEchelonGraph re-scored
  14. 2026-10-20 09:07 UTCVendor advisory
  15. 2026-10-20 09:06 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  16. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  17. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  18. 2026-10-18 03:12 UTCEchelonGraph re-scored
  19. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  20. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  21. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  22. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  23. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  24. 2026-10-13 07:07 UTCEchelonGraph re-scored
  25. 2026-10-13 07:07 UTCVendor advisory
  26. 2026-10-13 07:07 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  27. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  28. 2026-10-12 15:38 UTCEchelonGraph re-scored
  29. 2026-10-11 19:24 UTCEchelonGraph re-scored
  30. 2026-10-11 16:39 UTCEchelonGraph re-scored
  31. 2026-10-11 13:58 UTCEchelonGraph re-scored
  32. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 27th percentile
  33. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  34. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  35. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  36. 2026-10-08 05:22 UTCEchelonGraph re-scored
  37. 2026-10-08 05:22 UTCVendor advisory
  38. 2026-10-08 05:22 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  39. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  40. 2026-10-07 05:27 UTCVendor advisory
  41. 2026-10-07 05:27 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  42. 2026-10-06 16:53 UTCEchelonGraph re-scored
  43. 2026-10-06 16:53 UTCVendor advisory
  44. 2026-10-06 16:53 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  45. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  46. 2026-10-06 03:25 UTCVendor advisory
  47. 2026-10-06 03:25 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  48. 2026-10-06 03:24 UTCEchelonGraph re-scored
  49. 2026-10-06 03:24 UTCVendor advisory
  50. 2026-10-06 03:24 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  51. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  52. 2026-10-05 09:29 UTCEchelonGraph re-scored
  53. 2026-10-05 09:29 UTCVendor advisory
  54. 2026-10-05 09:29 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  55. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  56. 2026-10-04 20:52 UTCVendor advisory
  57. 2026-10-04 20:52 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  58. 2026-10-04 05:20 UTCVendor advisory
  59. 2026-10-04 05:20 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  60. 2026-10-03 16:47 UTCEchelonGraph re-scored
  61. 2026-10-03 16:47 UTCVendor advisory
  62. 2026-10-03 16:47 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  63. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  64. 2026-10-02 19:22 UTCEchelonGraph re-scored
  65. 2026-10-02 19:22 UTCVendor advisory
  66. 2026-10-02 19:22 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  67. 2026-10-02 06:49 UTCEchelonGraph re-scored
  68. 2026-10-02 06:49 UTCVendor advisory
  69. 2026-10-02 06:49 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  70. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 26th percentile
  71. 2026-10-01 15:29 UTCEchelonGraph re-scored
  72. 2026-10-01 15:29 UTCVendor advisory
  73. 2026-10-01 15:28 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5
  74. 2026-10-01 09:19 UTCVendor advisory
  75. 2026-10-01 09:19 UTCGHSA enrichmentGHSA-r6r4-8m79-7vvv · GitHub severity HIGH · GitHub CVSS 7.5

Frequently asked(5)

What is CVE-2026-76641?
CVE-2026-76641 is a high-severity vulnerability; its CVE record was published on August 20, 2026. Expat through 2.8.3 contains an out-of-bounds read vulnerability that allows attackers to trigger memory corruption by processing XML with external entity parsers created via XML_ExternalEntityParserCreate. A struct size mismatch between ELEMENT_TYPE members causes storeAtts to read the attIndex…
When was CVE-2026-76641 made public?
CVE-2026-76641 was made public on August 19, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on August 20, 2026. EchelonGraph's copy of the record carries a last-modified date of November 8, 2026; the record at its source may have been updated since.
Is CVE-2026-76641 actively exploited?
CVE-2026-76641 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (29th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-76641?
CVE-2026-76641 has a CVSS base score of 7.5 (the CNA's own assessment, by vulncheck; NVD's own analysis pending).
How do I remediate CVE-2026-76641?
A fix for CVE-2026-76641 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-76641 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-76641

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