7.5

CVE-2026-114613: MessagePack: Unbounded memory leak in msgpack C extension on strict_map_key validation failure

Awaiting analysis
AliasesDEBIAN-CVE-2026-114613GHSA-j586-36cw-2gc2CGA-2f4h-6mfp-prmq
Published 22-10-2026Last modified 23-10-2026

Vulnerability summary

CVE-2026-114613 is a high (CVSS 7.5) vulnerability in msgpack msgpack-python. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 45.6% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.5 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.54%
0%100%
Low · Change unavailable
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 22-10-2026
    PublishedVulnerability first disclosed.
  2. 23-10-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

6 scores · 6 sources · 1 version

EPSS trend

Probability

0.54%

Chance of exploitation in the next 30 days

Percentile

46%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

23-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard144 products
  • airflow-2All versions (No fix recorded)
  • authentik-2025.12All versions (No fix recorded)
  • authentik-2026.2All versions (No fix recorded)
  • authentik-fips-2025.12All versions (No fix recorded)
  • awx< 24.6.1-r76 | All versions (No fix recorded)
Wolfi23 products
  • datadog-agent-7.78All versions (No fix recorded)
  • datadog-agent-7.78-core-integrationsAll versions (No fix recorded)
  • datadog-agent-7.79All versions (No fix recorded) | < 7.79.2-r32
  • datadog-agent-7.79-core-integrationsAll versions (No fix recorded)
  • datadog-agent-7.80All versions (No fix recorded)
Debian1 product
  • python-msgpackAll versions (No fix recorded)
Msgpack1 product
PyPI1 product
  • msgpack< 1.2.3

5 vendors · 170 products

References

7 links