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NVD / CVE Program· CNA GitHub_M

CVE-2026-45067: Symfony: Email Header / SMTP Command Injection via CRLF in Symfony\Component\Mime\Address

Noroxi assessment

Priority: Monitor (action score 25/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.59% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: symfony (Debian:12) 5.4.53+dfsg-0+deb12u1; symfony (Debian:13) 6.4.41+dfsg-0+deb13u1; symfony (Debian:14) 7.4.12+dfsg-1.

Low priority for now. Upgrade to symfony (Debian:12) 5.4.53+dfsg-0+deb12u1; symfony (Debian:13) 6.4.41+dfsg-0+deb13u1; symfony (Debian:14) 7.4.12+dfsg-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

### Description `Symfony\Component\Mime\Address` is the value-object every Symfony Mailer address (to/cc/bcc/from/reply-to) flows through; its constructor is documented as validating the address and throwing on invalid input, so developers treat it as a security boundary. The constructor accepts email addresses whose local-part (the part before `@`) is an RFC-5322 *quoted string* containing raw `\r\n` bytes — e.g. `"x\r\nBcc: attacker@evil"@example.com`. The stored address is later emitted verbatim into (1) the rendered message headers and (2) `SmtpTransport`'s `MAIL FROM:<...>` / `RCPT TO:<...>` protocol lines, turning the embedded CRLF into a new mail header and/or a new SMTP command. ### Resolution The `Address` constructor now rejects addresses containing line breaks. The patch for this issue is available [here](https://github.com/symfony/symfony/commit/dc2dbd29211eb4ddc451373fa1374fb926e94604) for branch 5.4. ### Credits We would like to thank Claude Mythos Preview (via Project Glasswing) for reporting the issue and providing the fix.

MediumCVSS 6.3 · v4.0—Proof of concept Fix available
Published
Jul 14, 2026
Updated
Jul 14, 2026
EPSS
0.5% · 48th percentile

Report tools

JSON

Action score

25

Monitor

Low priority for now.

CVSS
25 / 40 · 6.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
6.3
NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • symfony symfony

    • < 5.4.52, >= 6.0.0-BETA1, < 6.4.40, >= 7.0.0-BETA1, < 7.4.12, >= 8.0.0-BETA1, < 8.0.12affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12symfonybefore 5.4.53+dfsg-0+deb12u15.4.53+dfsg-0+deb12u1
Debian:13symfonybefore 6.4.41+dfsg-0+deb13u16.4.41+dfsg-0+deb13u1
Debian:14symfonybefore 7.4.12+dfsg-17.4.12+dfsg-1
Packagistsymfony/mimefrom 6.0.0 · before 6.4.406.4.40
Packagistsymfony/mimefrom 7.0.0 · before 7.4.127.4.12
Packagistsymfony/mimefrom 8.0.0 · before 8.0.128.0.12
Packagistsymfony/mimebefore 5.4.525.4.52
Packagistsymfony/symfonyfrom 6.0.0 · before 6.4.406.4.40
Packagistsymfony/symfonyfrom 7.0.0 · before 7.4.127.4.12
Packagistsymfony/symfonyfrom 8.0.0 · before 8.0.128.0.12
Packagistsymfony/symfonybefore 5.4.525.4.52

Same product

symfony: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-50340Ability to change environment from query in symfony/runtime
    48Plan
  • CVE-2024-51996Symphony has an Authentication Bypass via RememberMe
    30Monitor
  • CVE-2026-118514Symfony: HEAD Requests Bypass the methods Option of security.access_control Rules and Firewalls
    25Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2024-50341Nov 6, 2024 · Security::login does not take into account custom user_checker in symfony/security-bundle
    12Monitor
  • ← EarlierCVE-2024-50343Nov 6, 2024 · Incorrect response from Validator when input ends with `\n` in symfony/validator
    12Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:symfony5.4.53+dfsg-0+deb12u1 · Debian:12Package registry (OSV)
Packagist:symfony/mime5.4.52Package registry (OSV)
Packagist:symfony/mime6.4.40Package registry (OSV)
Packagist:symfony/mime7.4.12Package registry (OSV)
Packagist:symfony/mime8.0.12Package registry (OSV)
Packagist:symfony/symfony5.4.52Package registry (OSV)
Packagist:symfony/symfony6.4.40Package registry (OSV)
Packagist:symfony/symfony7.4.12Package registry (OSV)
Packagist:symfony/symfony8.0.12Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:02026-06-09

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. First PoC-36 d
  2. Published
  3. TodayNov 10, 2026+119 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-93 · Improper Neutralization of CRLF Sequences ('CRLF Injection')

CVSS vector

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-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

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Change log

  1. Fix✗ → ✓

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References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records