CVE-2026-4426

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory published 2026-03-19. NVD baseline CVSS 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0

A fix is available — apply it.

A flaw was found in libarchive. An Undefined Behavior vulnerability exists in the zisofs decompression logic, caused by improper validation of a field (pz_log2_bs) read from ISO9660 Rock Ridge extensions. A remote attacker can exploit this by supplying a specially crafted ISO file. This can lead to incorrect memory allocation and potential application crashes, resulting in a denial-of-service (DoS) condition.

CVSS v3
6.5
EG Score
6.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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
Severity65% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
23%
KEV
Not listed

Published

March 19, 2026

Last Modified

September 1, 2026

Advisory Details (4)

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

iso9660: validate pz_log2_bs in parse_rockridge_ZF1() by ElhananHaenel · Pull Request #2897 · libarchive/libarchive · GitHub

https://github.com/libarchive/libarchive/pull/2897
redhat Patch Available

2449010 – (CVE-2026-4426) CVE-2026-4426 libarchive: libarchive: Denial of Service via malformed ISO file processing

https://bugzilla.redhat.com/show_bug.cgi?id=2449010
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-4426
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:8944

Vendor Advisories for CVE-2026-4426(2)

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

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibarchive13t64 (3.7.7-0ubuntu3.2) @ questing2026-08-21ubuntu
redhatlibarchive-main-3.8.7-1.hum12026-04-20redhat

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
libarchive3.4.3-2, 3.4.3-2+deb11u1, 3.4.3-2+deb11u2, 3.4.3-2+deb11u33.4.3-2+deb11u4—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
libarchive3.6.2-1, 3.6.2-1+deb12u1, 3.6.2-1+deb12u2, 3.6.2-1+deb12u33.6.2-1+deb12u4—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
libarchive3.7.4-43.7.4-4+deb13u1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
libarchive3.7.4-4, 3.8.4-1, 3.8.5-1, 3.8.6-13.8.7-1—

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 4× in last 7d / 34× 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 187 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-4426?
CVE-2026-4426 is a medium vulnerability published on March 19, 2026. A flaw was found in libarchive. An Undefined Behavior vulnerability exists in the zisofs decompression logic, caused by improper validation of a field (pzlog2bs) read from ISO9660 Rock Ridge extensions. A remote attacker can exploit this by supplying a specially crafted ISO file. This can lead to…
When was CVE-2026-4426 disclosed?
CVE-2026-4426 was first published in the National Vulnerability Database on March 19, 2026, with the most recent update on September 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-4426 actively exploited?
CVE-2026-4426 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 76.6% of all scored CVEs.
What is the CVSS score of CVE-2026-4426?
CVE-2026-4426 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-4426?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-4426, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-4426

Explore →

Is Your Infrastructure Affected by CVE-2026-4426?

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

Start Free Scan →Browse All CVEs