CVE-2026-34743

MEDIUMNVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 63% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: None knownExposed: 0

A fix is available — apply it.

XZ Utils provide a general-purpose data-compression library plus command-line tools. Prior to version 5.8.3, if lzma_index_decoder() was used to decode an Index that contained no Records, the resulting lzma_index was left in a state where where a subsequent lzma_index_append() would allocate too little memory, and a buffer overflow would occur. This issue has been patched in version 5.8.3.

CVSS v3
5.3
EG Score
5.3(medium)
EG Risk
39(Track)
EG Risk 39/100SSVC: 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
Severity53% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
38%
KEV
Not listed

Published

April 2, 2026

Last Modified

July 24, 2026

Advisory Details (5)

Auto-updated Jul 22, 2026
Patch available. Sources: github_commit, github_release, github.
generic Patch Available

[SECURITY] [DLA 4690-1] xz-utils security update

https://lists.debian.org/debian-lts-announce/2026/07/msg00034.html
generic

oss-security - Fwd: XZ Utils 5.8.3 and a security fix

http://www.openwall.com/lists/oss-security/2026/03/31/13
github Patch Available

XZ Utils: Buffer overflow in lzma_index_append() · Advisory · tukaani-project/xz · GitHub

https://github.com/tukaani-project/xz/security/advisories/GHSA-x872-m794-cxhv
github_release Patch Available

XZ Utils 5.8.3 (stable)

Patch available: tukaani-project/xz v5.8.3

https://github.com/tukaani-project/xz/releases/tag/v5.8.3
github_commit

commit c8c22869e780 (tukaani-project/xz)

Fix landed in tukaani-project/xz commit c8c22869e780 — awaiting tagged release

https://github.com/tukaani-project/xz/commit/c8c22869e780ff57c96b46939c3d79ff99395f87

Vendor Advisories for CVE-2026-34743(3)

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
ubuntuxzdec (5.2.4-1ubuntu1.1+esm1) @ focal2026-07-26ubuntu
redhatxz-main-5.8.3-1.1.hum12026-04-11redhat

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

(9 across 9 ecosystems)
Alpine:v3.20(1)
PackageVulnerable rangeFixed inDependents
xz—5.8.3-r0—
Alpine:v3.21(1)
PackageVulnerable rangeFixed inDependents
xz—5.8.3-r0—
Alpine:v3.22(1)
PackageVulnerable rangeFixed inDependents
xz—5.8.3-r0—
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
xz—5.8.3-r0—
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
xz—5.8.3-r0—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
xz-utils5.2.5-2, 5.2.5-2.1~deb11u15.2.5-2.1~deb11u2—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
xz-utils5.4.1-0.2, 5.4.1-15.4.1-1+deb12u1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
xz-utils5.8.1-15.8.1-1+deb13u1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
xz-utils5.8.1-1, 5.8.1-1.1, 5.8.1-2, 5.8.2-1, 5.8.2-25.8.3-1—

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 7× in last 7d / 29× 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 177 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-34743?
CVE-2026-34743 is a medium vulnerability published on April 2, 2026. XZ Utils provide a general-purpose data-compression library plus command-line tools. Prior to version 5.8.3, if lzmaindexdecoder() was used to decode an Index that contained no Records, the resulting lzmaindex was left in a state where where a subsequent lzmaindex_append() would allocate too little…
When was CVE-2026-34743 disclosed?
CVE-2026-34743 was first published in the National Vulnerability Database on April 2, 2026, with the most recent update on July 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-34743 actively exploited?
CVE-2026-34743 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 62.0% of all scored CVEs.
What is the CVSS score of CVE-2026-34743?
CVE-2026-34743 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-34743?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-34743, 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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