CVE-2026-18477

MEDIUMPre-NVD 4.44.4
EchelonGraph scoreMEDIUM confidence

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

Score 4.4 from GitHub Security Advisory (severity: MODERATE) published 2026-08-03. A secondary CVSS source baseline 4.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source

Also known asEUVD-2026-52336 (ENISA EUVD) · GHSA-v7fx-gjvh-347c (GitHub Security Advisories)Source: ENISA EUVD

4.4EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 4.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

A TOCTOU (Time-of-Check Time-of-Use) vulnerability in GNU tar's incremental dumpdir 'X' rename handling allows a local attacker with write access to a directory being backed up to influence the restore process if the attacker has access to the system where the restore is being performed. During restoration, files or directories may be created, renamed or overwritten outside the intended extraction directory. This could lead to unauthorized file modification or, in some cases, privilege escalation. Exploitation does not require the attacker to modify or craft the archive, and standard backup and restore workflows—including extracting into a newly created directory without using the -P option do not mitigate the issue.

CVSS v3
4.4
EG Score
4.4MEDIUMmedium confidence
EG Risk
20
EG Risk 20/100

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)
Severity44% × 45%
Impact severity (EG Severity): CVSS 4.4 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation<0.1% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (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.
EPSS PROB
0.1%
EPSS %ILE
1st
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 (4.4): severity, escalated by confirmed exploitation. This CVE's 4.4 is its impact severity (EG Severity), not escalated.

EG Severity
4.4 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.1% within 30 daysSource: FIRST EPSS. 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 every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade 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 every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (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 3, 2026

Last Modified

November 5, 2026

Advisory Details (2)

Auto-updated Aug 3, 2026
Patch available. Sources: redhat.
Red Hat

Bug Access Denied

https://bugzilla.redhat.com/show_bug.cgi?id=2509735
Red HatMentions a patch (unverified)

CVE-2026-18477 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-18477

Vendor Advisories for CVE-2026-18477(8)

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

Patch Availability(6)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhattar-2:1.30-13.el8_102026-09-22redhat
redhatrhui5/rhua-rhel9:17888805812026-09-09redhat
redhattar-2:1.35-13.el10_22026-09-01redhat
redhattar-2:1.34-13.el9_82026-08-31redhat
redhatdiscovery/discovery-server-rhel9:17882057792026-08-31redhat
redhattar-main-1.35-9.1.hum12026-08-01redhat

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)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
tar1.34+dfsg-1 ... 1.35+dfsg-4 (11 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
tar1.34+dfsg-1.2 ... 1.35+dfsg-7 (13 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
tar1.35+dfsg-3.1 ... 1.35+dfsg-7 (6 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
tar1.35+dfsg-3.1 ... 1.35+dfsg-7 (6 versions)
  • every version on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 4× in last 7d / 26× 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 270 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 170 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  2. 2026-11-11 16:38 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  3. 2026-11-08 16:38 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  4. 2026-11-07 16:38 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  5. 2026-11-05 20:29 UTCEchelonGraph re-scored
  6. 2026-11-05 20:29 UTCVendor advisory
  7. 2026-11-05 20:29 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub severity MODERATE · GitHub CVSS 4.4
  8. 2026-11-05 19:33 UTCEchelonGraph re-scored
  9. 2026-11-05 19:33 UTCVendor advisory
  10. 2026-11-05 19:33 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub severity MODERATE · GitHub CVSS 4.4
  11. 2026-11-05 16:37 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  12. 2026-11-04 16:35 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  13. 2026-11-03 16:47 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  14. 2026-11-02 16:44 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  15. 2026-10-31 16:32 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  16. 2026-10-30 19:33 UTCEchelonGraph re-scored
  17. 2026-10-30 19:33 UTCVendor advisory
  18. 2026-10-30 19:33 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  19. 2026-10-30 18:55 UTCEchelonGraph re-scored
  20. 2026-10-30 18:55 UTCVendor advisory
  21. 2026-10-30 18:55 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  22. 2026-10-30 16:33 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  23. 2026-10-29 16:32 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  24. 2026-10-28 16:31 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  25. 2026-10-27 16:31 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
Show 75 more
  1. 2026-10-25 16:32 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  2. 2026-10-25 14:45 UTCEchelonGraph re-scored
  3. 2026-10-23 05:59 UTCEchelonGraph re-scored
  4. 2026-10-23 05:59 UTCVendor advisory
  5. 2026-10-23 05:59 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  6. 2026-10-19 16:31 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  7. 2026-10-18 03:58 UTCEchelonGraph re-scored
  8. 2026-10-15 16:31 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  9. 2026-10-12 16:33 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  10. 2026-10-12 16:27 UTCEchelonGraph re-scored
  11. 2026-10-11 20:07 UTCEchelonGraph re-scored
  12. 2026-10-11 17:20 UTCEchelonGraph re-scored
  13. 2026-10-11 14:52 UTCEchelonGraph re-scored
  14. 2026-10-10 19:59 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  15. 2026-10-08 17:11 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  16. 2026-10-07 23:47 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  17. 2026-10-06 23:46 UTCEchelonGraph re-scored
  18. 2026-10-06 23:46 UTCVendor advisory
  19. 2026-10-06 23:46 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  20. 2026-10-06 15:17 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  21. 2026-10-05 19:48 UTCEchelonGraph re-scored
  22. 2026-10-05 19:48 UTCVendor advisory
  23. 2026-10-05 19:48 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  24. 2026-10-05 17:42 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  25. 2026-10-04 06:19 UTCEchelonGraph re-scored
  26. 2026-10-04 06:19 UTCVendor advisory
  27. 2026-10-04 06:19 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  28. 2026-10-03 14:25 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  29. 2026-10-02 10:18 UTCVendor advisory
  30. 2026-10-02 10:18 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  31. 2026-10-01 02:33 UTCVendor advisory
  32. 2026-10-01 02:33 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  33. 2026-09-29 06:39 UTCEchelonGraph re-scored
  34. 2026-09-29 06:39 UTCVendor advisory
  35. 2026-09-29 06:39 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  36. 2026-09-27 18:15 UTCEchelonGraph re-scored
  37. 2026-09-27 18:15 UTCVendor advisory
  38. 2026-09-27 18:15 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  39. 2026-09-26 15:58 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  40. 2026-09-25 04:46 UTCEchelonGraph re-scored
  41. 2026-09-25 04:46 UTCVendor advisory
  42. 2026-09-25 04:46 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  43. 2026-09-24 00:16 UTCEchelonGraph re-scored
  44. 2026-09-24 00:16 UTCVendor advisory
  45. 2026-09-24 00:16 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  46. 2026-09-22 22:35 UTCEchelonGraph re-scored
  47. 2026-09-22 22:35 UTCVendor advisory
  48. 2026-09-22 22:35 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  49. 2026-09-22 21:33 UTCEchelonGraph re-scored
  50. 2026-09-22 21:33 UTCVendor advisory
  51. 2026-09-22 21:33 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  52. 2026-09-22 05:28 UTCVendor advisory
  53. 2026-09-22 05:28 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  54. 2026-09-20 20:56 UTCEchelonGraph re-scored
  55. 2026-09-20 20:56 UTCVendor advisory
  56. 2026-09-20 20:56 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  57. 2026-09-19 13:33 UTCEchelonGraph re-scored
  58. 2026-09-19 13:33 UTCVendor advisory
  59. 2026-09-19 13:33 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  60. 2026-09-18 19:27 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  61. 2026-09-18 08:38 UTCEchelonGraph re-scored
  62. 2026-09-18 08:38 UTCVendor advisory
  63. 2026-09-18 08:38 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  64. 2026-09-17 07:02 UTCEchelonGraph re-scored
  65. 2026-09-17 07:02 UTCVendor advisory
  66. 2026-09-17 07:02 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  67. 2026-09-16 14:07 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  68. 2026-09-16 05:18 UTCEchelonGraph re-scored
  69. 2026-09-16 05:18 UTCVendor advisory
  70. 2026-09-16 05:18 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  71. 2026-09-15 01:55 UTCVendor advisory
  72. 2026-09-15 01:55 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  73. 2026-09-13 23:39 UTCVendor advisory
  74. 2026-09-13 23:39 UTCGHSA enrichmentGHSA-v7fx-gjvh-347c · GitHub CVSS 4.4
  75. 2026-09-12 22:03 UTCEchelonGraph re-scored

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-18477?
CVE-2026-18477 is a medium-severity vulnerability; its CVE record was published on August 3, 2026. A TOCTOU (Time-of-Check Time-of-Use) vulnerability in GNU tar's incremental dumpdir 'X' rename handling allows a local attacker with write access to a directory being backed up to influence the restore process if the attacker has access to the system where the restore is being performed. During…
When was CVE-2026-18477 made public?
CVE-2026-18477 was made public on July 31, 2026: that is the date its CVE record's CNA, Red Hat, Inc., gives for when the vulnerability was made public. The CVE record itself was published on August 3, 2026. EchelonGraph's copy of the record carries a last-modified date of November 5, 2026; the record at its source may have been updated since.
Is CVE-2026-18477 actively exploited?
CVE-2026-18477 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (1st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-18477?
CVE-2026-18477 has a CVSS base score of 4.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-18477?
A fix for CVE-2026-18477 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-18477 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-2026-18477

Explore →

Is Your Infrastructure Affected by CVE-2026-18477?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs