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CVE-2026-116742VulnerabilityPublished Updated

HTSlib through 1.24 contains a heap out-of-bounds write and read vulnerability in bgzf_index_load_hfile() in bgzf.c

Affects htslibSource GCVE Database

0
Authoritative record:CVE-2026-116742· Medium 4.8

Not known to be exploited · CVSS 4.8 Medium.

Data as of 28 Oct 2026, 22:33 UTC

CVSS 4.0 base score
4.8Medium
How severe the flaw is on the 0–10 CVSS scale.
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 26 Oct 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

Affected software

ProductAffectedFixed in
Ubuntu 26.10htslibpkg:deb/ubuntu/htslib?arch=source&distro=stonkingOther threatsAffected
  • =1.22.1+ds2-1
  • =1.22.1+ds2-1build1
Fixed in–
Ubuntu 26.04 LTShtslibpkg:deb/ubuntu/htslib?arch=source&distro=resoluteOther threatsAffected
  • =1.21+ds-1
  • =1.22.1+ds2-1
Fixed in–
Ubuntu 24.04 LTShtslibpkg:deb/ubuntu/htslib?arch=source&distro=nobleOther threatsAffected
  • 1.17+ds-1 – 1.19+ds-1.1build3
4 affected builds
Fixed in–
Ubuntu 22.04 LTShtslibpkg:deb/ubuntu/htslib?arch=source&distro=jammyOther threatsAffected
  • =1.13+ds-2
  • =1.13+ds-2build1
Fixed in–
Ubuntu 20.04 LTShtslibpkg:deb/ubuntu/htslib?arch=source&distro=focalOther threatsAffected
  • 1.9-10 – 1.10.2-3ubuntu0.1
7 affected builds
Fixed in–
Ubuntu Pro 18.04 LTShtslibpkg:deb/ubuntu/htslib?arch=source&distro=esm-apps/bionicOther threatsAffected
  • 1.5-1 – 1.7-2ubuntu0.1~esm1
7 affected builds
Fixed in–

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

AI-suggested

Until a fix is available, users should avoid processing untrusted .gzi index files or use alternative mitigations recommended by the vendor once published.

Description

HTSlib versions through 1.24 contain a heap out-of-bounds write and read vulnerability in the function bgzf_index_load_hfile() within bgzf.c. This flaw allows attackers to corrupt heap memory by providing a crafted .gzi index entry count. Specifically, a count value of 0xFFFFFFFF causes truncation of noffs to zero, leading to writes beyond a malloc(0) buffer and an out-of-bounds read in bgzf_useek(), which can cause heap corruption or crashes in tools such as samtools and bcftools.

References

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