CVE-2026-18477

MEDIUMPre-NVD 4.44.4—
EchelonGraph scoreMEDIUM confidence

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

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
4.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • 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 20/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity44% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
<0.1%
EPSS %ILE
below the 1st
KEV
Not listed

CISA SSVCTrack 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). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 3, 2026

Last Modified

September 22, 2026

Advisory Details (2)

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

Bug Access Denied

https://bugzilla.redhat.com/show_bug.cgi?id=2509735
redhat Patch Available

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(6)

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-6 (12 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
tar1.35+dfsg-3.1, 1.35+dfsg-4, 1.35+dfsg-5, 1.35+dfsg-5+hurd.1, 1.35+dfsg-6
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
tar1.35+dfsg-3.1, 1.35+dfsg-4, 1.35+dfsg-5, 1.35+dfsg-5+hurd.1, 1.35+dfsg-6
  • every version on: no fix on record
—

Weakness Classification(1)

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

Additional Vendor Advisories

(2)

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 11× in last 7d / 81× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 221 total refreshes for this CVE.

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

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

Frequently asked(5)

What is CVE-2026-18477?
CVE-2026-18477 is a medium vulnerability 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 disclosed?
CVE-2026-18477 was first published on August 3, 2026, with the most recent update on September 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
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 (below the 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

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