CVE-2026-87735
An issue was discovered in the mirage-crypto-pk package before 2.3.0 for OCaml. There is an...
An issue was discovered in the mirage-crypto-pk package before 2.3.0 for OCaml. There is an undocumented exception for a small message during RSA decryption or encryption.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
An issue was discovered in the mirage-crypto-pk package before 2.3.0 for OCaml. There is an undocumented exception for a small message during RSA decryption or encryption.
- Record
CVE-2026-87735- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-1284
- Updated
- 2026-11-02
EUVDEUVD-2026-74621
An issue was discovered in the mirage-crypto-pk package before 2.3.0 for OCaml. There is an undocumented exception for a small message during RSA decryption or encryption.
- Record
EUVD-2026-74621- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-7mc7-qjpc-23j7
An issue was discovered in the mirage-crypto-pk package before 2.3.0 for OCaml. There is an...
An issue was discovered in the mirage-crypto-pk package before 2.3.0 for OCaml. There is an undocumented exception for a small message during RSA decryption or encryption.
- Record
GHSA-7mc7-qjpc-23j7- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-1284
- Updated
- 2026-11-02
NVD
An issue was discovered in the mirage-crypto-pk package before 2.3.0 for OCaml. There is an undocumented exception for a small message during RSA decryption or encryption.
- Record
CVE-2026-87735- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-1284
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-87735
An issue was discovered in the mirage-crypto-pk package before 2.3.0 for OCaml. There is an undocumented exception for a small message during RSA decryption or encryption.
- Record
DEBIAN-CVE-2026-87735- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-02
OSVOSEC-2026-14
RSA signature verification raises undocumented exception
The RSA decrypt and encrypt functions raise an Invalid_argument exception if the message is smaller than 2. This leads to X509 certificates with a signature value of 0 or 1 to throw this Invalid_argument exception instead of a proper error.
Fix
The fix is to reuse the Insufficient_key exception, which is documented and caught further up in the stack.
Timeline
- July 28th 2026: report to [email protected]
- August 7th: release of mirage-crypto-pk 2.3.0 and security advisory
- Record
OSEC-2026-14- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-87735
An issue was discovered in the mirage-crypto-pk package before 2.3.0 for OCaml. There is an undocumented exception for a small message during RSA decryption or encryption.
- Record
UBUNTU-CVE-2026-87735- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
ocaml-mirage-cryptoDebian:12 |
All versions, plus listed versions 0.10.7-10.11.1-10.11.1-20.11.1-30.11.2-1 Show 14 moreShow less0.11.2-20.11.3-11.1.0-11.1.0-22.0.0-12.0.1-12.0.2-12.0.3-12.1.0-12.2.0-12.2.0-22.3.0-12.4.0-12.4.1-1 |
None known |
ocaml-mirage-cryptoDebian:13 |
All versions, plus listed versions 2.0.0-12.0.1-12.0.2-12.0.3-12.1.0-1 Show 5 moreShow less2.2.0-12.2.0-22.3.0-12.4.0-12.4.1-1 |
None known |
ocaml-mirage-cryptoDebian:14 |
before 2.3.0-1, plus listed versions 2.0.0-12.0.1-12.0.2-12.0.3-12.1.0-12.2.0-12.2.0-2 |
2.3.0-1 |
mirage-crypto-pkopam |
before 2.3.0, plus listed versions 0.6.00.6.10.6.20.7.00.8.0 Show 45 moreShow less0.8.10.8.20.8.30.8.40.8.50.8.60.8.70.8.80.8.90.8.100.9.00.9.10.9.20.10.00.10.10.10.20.10.30.10.40.10.50.10.60.10.70.11.00.11.10.11.20.11.31.0.01.1.01.2.02.0.02.0.12.0.22.0.32.1.02.2.0v2.2.0v2.1.0v2.0.3v2.0.2v2.0.1v2.0.0v1.2.0v1.1.0v1.0.1v1.0.0v0.11.3 |
2.3.0 |
ocaml-mirage-cryptoUbuntu:22.04:LTS |
All versions, plus listed versions 0.10.5-40.10.5-4build2 |
None known |
ocaml-mirage-cryptoUbuntu:24.04:LTS |
All versions, plus listed versions 0.11.1-30.11.2-10.11.2-1build10.11.2-2build3 |
None known |
ocaml-mirage-cryptoUbuntu:26.10 |
All versions, plus listed versions 2.0.2-1build52.4.0-1 |
None known |
ocaml-mirage-cryptoUbuntu:26.04:LTS |
All versions, plus listed versions 2.0.1-1build12.0.2-1build12.0.2-1build22.0.2-1build32.0.2-1build5 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-87735 is a medium vulnerability (CVSS 4.3) in Ocaml Mirage-crypto-pk, published August 7, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.23%, the 13th percentile. Fixed in ocaml-mirage-crypto 2.3.0-1.
References
Left out here: 29 versions. The JSON record has them.