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CVE-2026-34743VulnerabilityPublished

Red Hat Security Advisory: xz security update

Affects Red Hat xzSource GCVE Database

0
Authoritative record:CVE-2026-34743· Low 1.7

Not known to be exploited · CVSS 1.7 Low : upgrade Red Hat xz to 5.8.3 when convenient.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 4.0 base score
1.7Low
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 5.8.3
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 2 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade xz and tukaani-project/xz to 5.8.3.

Affected software

ProductAffectedFixed in
tukaani-projectxzAffected
  • <5.8.3
Fixed in
  • 5.8.3
GitHubtukaani-project/xzpkg:github/tukaani-project/xzOther threatsAffected
  • <5.8.3
Fixed in
  • 5.8.3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

XZ Utils is an integrated collection of user-space file compression utilities based on the Lempel-Ziv-Markov chain algorithm (LZMA), which performs lossless data compression. The algorithm provides a high compression ratio while keeping the decompression time short. Security Fix(es): * xz: XZ Utils: Denial of Service via buffer overflow in index decoding (CVE-2026-34743) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

References

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