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CVE-2026-104874PYSEC-2026-4244GHSA-54P9-H82J-F925

Multidict: Reference leak in CIMultiDict/MultiDict items-view union and subtraction

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 6.9.1
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: poc
  • Automatable: yes
  • Technical impact: partial

Summary

Multidict is an implementation of a multidict data structure. From 6.7.0 until 6.9.1, the C extension's items-view reflected union operation, operand | d.items(), in multidict_itemsview_or2_impl and subtraction operation, d.items() - operand, in multidict_itemsview_sub1_impl fail to release new key-identity and value references returned for each operand element. Applications that perform these operations over attacker-influenced sequences can leak two strong references per element, and garbage collection cannot reclaim them, so repeated operations can cause unbounded process memory growth and denial of service. Forward union, intersection, non-tuple operand elements, and pure-Python builds are not affected by this reference leak. This issue is fixed in version 6.9.1.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: poc · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • aio-libs multidict

    From 6.7.0 · fixed in 6.9.1

  • multidictPyPI

    From 6.7.0 · fixed in 6.9.1

References 3

GitHub · aio-libs/multidict