CVE-2026-18508

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 flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets are not confined to the designated top-level directory and may resolve relative to the extraction working directory. A crafted archive can create hardlinks that escape the intended boundary and, when combined with a preexisting symbolic link under the working directory, may allow writing outside that boundary during a single extraction.

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
2nd
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=2509843
redhat Patch Available

CVE-2026-18508 - 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-2026-18508

Vendor Advisories for CVE-2026-18508(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-1.35-9.2.hum12026-08-05redhat

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 17× in last 7d / 91× 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 242 total refreshes for this CVE.

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

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

Frequently asked(5)

What is CVE-2026-18508?
CVE-2026-18508 is a medium vulnerability published on August 3, 2026. A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets are not confined to the designated top-level directory and may resolve relative to the extraction working directory. A crafted archive can create hardlinks that escape the intended boundary…
When was CVE-2026-18508 disclosed?
CVE-2026-18508 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-2026-18508 actively exploited?
CVE-2026-18508 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (2nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-18508?
CVE-2026-18508 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-2026-18508?
A fix for CVE-2026-18508 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-18508 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-2026-18508

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