CVE-2026-89087 json
Cstruct indexing bugs can corrupt filtered output and reverse parsing results
published 2026-09-10 59 d ago modified 2026-11-06 2 d ago also EUVD-2026-75709 , OSEC-2026-20
- cvss
- 7.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 24%
- public exploits
- 0
- none known
Summary
The cstruct package before 6.3.0 for OCaml mishandles indexes.
Patch / fix
- opam cstruct 6.3.0
- OCaml cstruct 6.3.0
- ocaml-cstruct Debian 14 6.3.0-1
debian advisories DEBIAN-CVE-2026-89087
- github.com/mirage/ocaml-cstruct#324 pull request
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 55 d ago
Exploit prediction
0.32% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 7.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L |
| OSV | 3.1 | 7.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| opam | cstruct | <6.3.0 |
6.3.0 |
Affected products
- OCaml cstruct
Classification
- Weakness
-
- CWE-573 Improper Following of Specification by Caller
References
Sources
- CVE List CVE-2026-89087
- NVD CVE-2026-89087
- OSV OSEC-2026-20
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.