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VulnerabilityPublished Updated

CVE-2026-59884: Parsedmarc · pyasn1 BER/CER/DER decoder denial of service via unbounded long-form tag IDs

Affects parsedmarcSource GCVE Database

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Not known to be exploited · CVSS 7.5 High : upgrade to 10.2.1 soon.

Data as of 1 Nov 2026, 00:23 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 10.2.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 31 Oct 2026.

What to do

Upgrade parsedmarc to 10.2.1.

Affected software

ProductAffectedFixed in
Homebrewparsedmarcpkg:brew/parsedmarcOther threatsAffected
  • >=8.11.0 <10.2.1
Fixed in
  • 10.2.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available in parsedmarc version 10.2.1 (pyasn1 0.6.4) which limits long-form tag IDs to 20 octets and improves error handling. Users should upgrade to this fixed version. As a workaround, applications can bound the size of untrusted input passed to the decode() function to prevent excessive resource consumption. No other mitigations are specified.

Description

A denial of service vulnerability exists in the pyasn1 BER/CER/DER decoder used by parsedmarc, caused by unbounded long-form tag IDs. The decoder accumulates continuation octets without an upper limit, allowing crafted inputs to cause excessive CPU consumption. On Python 3.11 and later, this can also trigger unhandled ValueError exceptions during error message formatting, potentially bypassing error handling. The issue affects decoding of untrusted BER/CER/DER inputs and was fixed in version 10.2.1 by limiting tag ID length and improving error handling.

References

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