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%CVSS: 4.4Exploit: None knownExposed: 0

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
4.4(medium)
EG Risk
20(Track)
EG Risk 20/100SSVC: Track

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%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
0%
KEV
Not listed

Published

August 3, 2026

Last Modified

September 10, 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(5)

Vendor / EcosystemFixed in / PatchReleasedSource
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 rangeFixed inDependents
tar1.34+dfsg-1 ... 1.35+dfsg-4 (11 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
tar1.34+dfsg-1.2 ... 1.35+dfsg-5 (10 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
tar1.35+dfsg-3.1, 1.35+dfsg-4, 1.35+dfsg-5——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
tar1.35+dfsg-3.1, 1.35+dfsg-4, 1.35+dfsg-5——

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 19× in last 7d / 122× 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 186 total refreshes for this CVE.

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

Related CVEs(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 in the National Vulnerability Database on August 3, 2026, with the most recent update on September 10, 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% probability of exploitation in the next 30 days, which ranks it in the top 99.8% of all scored CVEs.
What is the CVSS score of CVE-2026-18477?
CVE-2026-18477 has a CVSS v3 base score of 4.4 (NVD).
How do I remediate CVE-2026-18477?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18477, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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