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CVE-2026-45066

LOW 2.3

Published 2026-07-14 · Last modified 2026-07-16

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, HtmlSanitizer URL sanitization can allow off-allowlist URLs through allowLinkHosts() or allowMediaHosts() because UrlSanitizer::parse() follows RFC 3986 while browsers follow WHATWG URL parsing, and because <area href> is checked against the media policy rather than the link policy. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.

NO EXPLOITATION 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 · 21st percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

2.3CVSS 4.0 · LOW

  • ConfidentialityNone
  • IntegrityNone
  • AvailabilityNone

What an attacker needs

  • Access: Reachable over the network — no local access needed
  • Privileges: No account or privileges required
  • User interaction: Succeeds with passive user activity
  • 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

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-45066/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-45066/poc.json

Affected

Vendors Symfony Sensiolabs

Products Symfony Html Sanitizer

Weakness (CWE)

  • CWE-184: : Incomplete List of Disallowed Inputs
  • CWE-436: : Interpretation Conflict

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/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 2.3 v4.0 · CNA Primary
    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
  • LOW 2.3 v4.0 · NVD Secondary
    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/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