Buffer overflow in Tukaani Xz
CVE-2026-34743
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…
Vulnerability class: Buffer Overflow
EPSS: 0.004 (27.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
Affected products
- Tukaani Xz
- Tukaani-project Xz — versions < 5.8.3
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Product, x_refsource_MISC, Release Notes)
- af854a3a-2127-422b-91ae-364da2661108 (Mailing List, Patch, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-34743?
- CVE-2026-34743 is a medium-severity vulnerability in Tukaani Xz, classified under Heap-based Buffer Overflow. CVSS score: 5.3/10. Published 2026-04-02.
- How severe is CVE-2026-34743?
- Medium severity. CVSS v3 base score is 5.3 out of 10.