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CVE-2026-45753

LOW 2.1 ALL-YEARS

Published 2026-07-14 · Last modified 2026-07-14 · GitHub_M · NVD: Analyzed

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, UrlAttributeSanitizer::getSupportedAttributes() omits URL-valued attributes including action, formaction, poster, and cite, so configurations that admit those attributes can leave javascript: URIs unsanitized and enable XSS when the resulting HTML is rendered or a victim submits a form or clicks a button. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.

LIMITED SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.3%chance of exploitation in 30 days · 22nd percentile

○ In CISA KEV○ Public exploit / PoC◆ SSVC: exploitation none, automatable no

Impact if exploited

2.1CVSS 4.0 · LOW · CNA

  • ConfidentialityNone
  • IntegrityNone
  • AvailabilityNone

What an attacker needs

  • Access: Reachable over the network — no local access needed
  • Privileges: No account or privileges required
  • User interaction: Requires active user interaction
  • Complexity: No special conditions — reliably repeatable
  • Requirements: Specific conditions must be present

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

No public exploit or proof-of-concept code is catalogued for this CVE (no ExploitDB, Nuclei, or CISA-KEV entry). It may still exist — search GitHub or check the references below.

Affected

Vendors Symfony Sensiolabs

Products Symfony Html Sanitizer

Weakness (CWE)

  • CWE-79: : Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
  • CWE-184: : Incomplete List of Disallowed Inputs

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Known Affected Software Configurations

VendorProductVersion range
SensiolabsSymfony≥ 6.1.0 and < 6.4.40
SensiolabsSymfony≥ 7.0.0 and < 7.4.12
SensiolabsSymfony≥ 8.0.0 and < 8.0.12

All CVSS metrics

  • LOW 2.1 v4.0 · CNA Primary
    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
  • LOW 2.1 v4.0 · NVD Secondary
    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/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
  • MEDIUM 6.1 v3.1 · NVD Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References

Technical & other

Sources: NVD · CVE.org · EPSS