CVE catalog
CVE-2026-114613
python-msgpack: CVE-2026-114613
- Severity
- High · CVSS 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.44% · Oct 25, 2026
MessagePack is the serializer implementation for Python msgpack.org. Prior to 1.2.3, the msgpack-python C extension (msgpack._cmsgpack) leaks a decoded map value when deserialization rejects a key with strict_map_key=True (the default). Repeated malformed inputs can cause unbounded process memory growth and denial of service in applications that deserialize attacker-controlled MessagePack data. Both unpackb() and the streaming Unpacker API are affected. The pure-Python fallback does not exhibit this leak in the reported tests. This issue is fixed in version 1.2.3.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | python-msgpack | sid | 1.2.1-3 | fixed |
| Debian | python-msgpack | forky | 1.2.1-1 | vulnerable |
| Debian | python-msgpack | trixie | 1.0.3-3 | vulnerable |
| Debian | python-msgpack | bookworm | 1.0.3-2 | vulnerable |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | python-msgpack | source | sid | 1.2.1-2 | not yet assigned | Not reported | [1151844] |
| Debian | python-msgpack | source | forky | (unfixed) | not yet assigned | Not reported | [1151844] |
| Debian | python-msgpack | source | trixie | (unfixed) | not yet assigned | Not reported | [1151844] |
| Debian | python-msgpack | source | bookworm | (unfixed) | not yet assigned | Not reported | [1151844] |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [python3-msgpack]Affected
Source package: [python-msgpack]
Details (2)
1.0.3-2+b1· amd64 · bookwormAffected
dsa · python-msgpack · debian · bookworm; dsa · python-msgpack · debian · 12
1.0.3-2+b1· arm64 · bookwormAffected
dsa · python-msgpack · debian · bookworm; dsa · python-msgpack · debian · 12
[Debian 13 (Trixie)]
- [python3-msgpack]Affected
Source package: [python-msgpack]
Details (2)
1.0.3-3+b4· amd64 · trixieAffected
dsa · python-msgpack · debian · 13
1.0.3-3+b5· arm64 · trixieAffected
dsa · python-msgpack · debian · 13
Observed:
References
- [https://github.com/msgpack/msgpack-python/commit/620b0eb4c89cd72d4098564537624d9dbb2ce141]
- [https://github.com/msgpack/msgpack-python/releases/tag/v1.2.3]
- [https://github.com/msgpack/msgpack-python/security/advisories/GHSA-j586-36cw-2gc2]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-114613]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-114613]
- [https://security-tracker.debian.org/tracker/CVE-2026-114613]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-114613.json]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]