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Fencer Intel
medium 6.5

CVE-2026-45070 json

Symfony: Email Header Injection via Non-Token Characters in Mime Parameter Names

published 5mo ago modified last mo. also GHSA-vqc8-7275-q272 , EUVD-2026-44346

cvss
6.5
version 3.1, NVD
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

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\Component\Mime\Header\ParameterizedHeader validates and encodes parameter values but emits parameter names verbatim, allowing a caller that derives a parameter name from untrusted input to include CRLF or other non-token bytes and inject additional headers into rendered structured mail headers such as Content-Type or Content-Disposition. This issue is reported as fixed in versions 5.4.52, 6.4.40, 7.4.12, and 8.0.12.

Patch / fix

  • packagist symfony/mime 5.4.52, 6.4.40, 7.4.12, 8.0.12
  • packagist symfony/symfony 5.4.52, 6.4.40, 7.4.12, 8.0.12
  • sensiolabs symfony 5.4.52, 6.4.40, 7.4.12, 8.0.12
  • symfony Debian 13 6.4.49+dfsg-0+deb13u1
  • symfony Debian 14 7.4.22+dfsg-1

debian advisories DEBIAN-CVE-2026-45070

Is CVE-2026-45070 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
3mo ago

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CNA 4.0 6.3 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
packagist symfony/mime
<5.4.52
>=6.0.0, <6.4.40
>=7.0.0, <7.4.12
>=8.0.0, <8.0.12
5.4.52
6.4.40
7.4.12
8.0.12
packagist symfony/symfony
<5.4.52
>=6.0.0, <6.4.40
>=7.0.0, <7.4.12
>=8.0.0, <8.0.12
5.4.52
6.4.40
7.4.12
8.0.12

Affected products

  • symfony symfony
  • symfony mime

Classification

Weakness
  • CWE-93 Improper Neutralization of CRLF Sequences

References

Sources

Fencer Intel 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.