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%CVSS: 4.4Exploit: None knownExposed: 0

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
4.4(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
4%
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=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(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-1.35-9.2.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 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 25× in last 7d / 137× 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 201 total refreshes for this CVE.

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

Related CVEs(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 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-2026-18508 actively exploited?
CVE-2026-18508 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 96.2% of all scored CVEs.
What is the CVSS score of CVE-2026-18508?
CVE-2026-18508 has a CVSS v3 base score of 4.4 (NVD).
How do I remediate CVE-2026-18508?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18508, 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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