CVE-2026-116742
What it is
HTSlib through 1.24 contains a heap out-of-bounds write and read vulnerability in bgzf_index_load_hfile() in bgzf.c that allows attackers to corrupt heap memory by supplying a crafted .gzi index entry count. A count of 0xFFFFFFFF truncates noffs to zero, causing writes past a malloc(0) buffer and an offs[-1] read in bgzf_useek(), resulting in heap corruption or crashes in tools like samtools and bcftools.
At a glance
- Exploitability
- Can be exploited locally on the machine without logging in, but needs a user to act. Limited direct impact.
- Exploit odds
- 0.1% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.1% in the next 30 days (EPSS).
- Severity: 4.8 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.1% · EPSS, next 30 days
- Weakness
- CWE-197
- Record status
- Deferred
Attack profile CVSS 4.0 · 4.8
- Attack vector
- Local
- Complexity
- Low
- Attack requirements
- None
- Privileges needed
- None
- User interaction
- Passive
- Confidentiality
- None
- Integrity
- Low
- Availability
- Low
Raw vector
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-116742.md and follow it. Check whether this project is affected by CVE-2026-116742. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/samtools/htslib/commit/18dddf02bb2c0053b32acec427723555a24b2873
- https://github.com/samtools/htslib/pull/2057
References
- https://github.com/samtools/htslib
- https://github.com/samtools/htslib/blob/1.24/bgzf.c#L2504
- https://github.com/samtools/htslib/commit/18dddf02bb2c0053b32acec427723555a24b2873
- https://github.com/samtools/htslib/issues/2113
- https://github.com/samtools/htslib/pull/2057
- https://hackmd.io/@haindpwn/htslib-bgzf-gzi-int-truncation-oob
- https://www.vulncheck.com/advisories/htslib-through-1.24-heap-out-of-bounds-write-via-truncated-gzi-index-count