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Fencer Vulns
high 7.5

CVE-2026-61816 json

zbateson/mail-mime-parser has uncontrolled resource consumption (CPU/memory DoS) parsing untrusted MIME

published 2026-09-24 45 d ago modified 2026-09-30 39 d ago also GHSA-f6v3-2qmr-vfjx , EUVD-2026-86336

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 33%
public exploits
0
none known

Summary

zbateson/mail-mime-parser is a mail mime parser alternative to PHP's imap* functions and Pear libraries for reading messages in Internet Message Format RFC 822. Starting in version 2.0.0 and prior to version 3.0.6 and 4.0.2, an uncontrolled resource consumption / algorithmic complexity vulnerability (CWE-400) affects any application that parses untrusted email with this library. Three independent parsing paths are super-linear in cost, so a byte-size cap on the caller side does **not** bound the work done. A crafted message under 2 MB can consume seconds of CPU or hundreds of megabytes to multiple gigabytes of memory (leading to an out-of-memory kill), enabling denial of service. The parse is lazy, but the cost is paid on the first `getAllParts()` or content read. This is fxed in 4.0.2 and 3.0.6. The fixes add configurable limits on multipart nesting depth and on header count / total header size (recording a parse error past the threshold rather than throwing), and change sibling append to O(n). Users should upgrade to one of these (or later) versions. Versions 2.x are also affected but are end-of-life and will not receive patches; users on those lines should upgrade to a fixed release. (Versions prior to 2.0 used a different parser and are not affected by all three paths.) These costs are super-linear, so an input byte-size cap alone does not bound them. Until upgrading, restrict exposure of the parser to untrusted input, and run parsing under a constrained memory_limit and execution time limit so a malicious message fails its own request rather than exhausting the host.

Patch / fix

  • packagist zbateson/mail-mime-parser 3.0.6, 4.0.2

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
45 d ago

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/zbateson/mail-mime-parser/security/advisories/GHSA-f6v3-2qmr-vfjx referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
packagist zbateson/mail-mime-parser
>=2.0.0, <3.0.6
>=4.0.0, <4.0.2
3.0.6
4.0.2

Affected products

  • zbateson mail-mime-parser

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.