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Algorithmic complexity denial of service in svg-sanitizer via use references

Priority MEDIUM 44CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-400.

Summary

svg-sanitizer from 0.11.0 before 1.1.0 by darylldoyle contains an algorithmic complexity denial of service flaw in hasInfiniteLoop() and countUse() of its use reference-graph analysis. An unauthenticated remote attacker can upload a small layered SVG with fanned-out use elements, forcing exponential path enumeration that ties up PHP workers for hours. The weakness is classified as CWE-400, Uncontrolled Resource Consumption.

Written with Claude Haiku 5.5 from the sources below · 2026-11-03

Description from the CNA

svg-sanitizer from 0.11.0 before 1.1.0 contains an algorithmic complexity denial of service vulnerability in hasInfiniteLoop() and countUse() of the use reference-graph analysis. Attackers can upload a small layered SVG with 15 levels of fanned-out use elements, forcing exponential path enumeration that pins PHP workers for hours.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00417 36th percentileScored 2026-11-07
Fix Fixed svg-sanitizer (darylldoyle): 1.1.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
darylldoylesvg-sanitizer0.11.0 to before 1.1.01.1.0Patch availableCNA
  • svg-sanitizer Vendordarylldoyle Affected 0.11.0 to before 1.1.0 Fixed in 1.1.0 Patch available CNA

Remediation

Upgrade svg-sanitizer to version 1.1.0, which fixes the flaw.

Written with Claude Haiku 5.5 from the sources below · 2026-11-03

  • Fix · CNA svg-sanitizer (darylldoyle) Fixed in 1.1.0

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    darylldoyle svg-sanitizer 1.1.0

    4 records Highest priority Priority HIGH 1 HIGH, 2 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-84327 svg-sanitizer ReDoS and Fail-Open via image-set CSS StrippingPriority HIGH 69
    • TI-2026-84328 Incomplete url() filtering in svg-sanitizer allows remote URL requestsPriority MEDIUM 57
    • TI-2026-84329 Cross-site scripting in svg-sanitizer via animateTransform on SafariPriority LOW 23

Timeline

  1. 2026-11-03 Threatist record created from CVE-2026-121444
  2. 2026-11-03 Alias added: GHSA-38xh-8h9r-v3mm
  3. 2026-11-03 CISA SSVC decision points changed

References

  • TI-2026-81116 Quadratic CPU exhaustion in svg-sanitizer PHP tag stripping CVSS 4.0HIGH 8.7
  • TI-2026-84327 svg-sanitizer ReDoS and Fail-Open via image-set CSS Stripping CVSS 4.0HIGH 8.2
  • TI-2026-74075 Mixed-case xlink:HrEf bypasses use nesting limit in svg-sanitizer CVSS 3.1MEDIUM 6.5
  • TI-2026-69645 Denial of service in enshrined/svg-sanitize via crafted SVG DTD CVSS 3.1MEDIUM 6.5
  • TI-2026-84328 Incomplete url() filtering in svg-sanitizer allows remote URL requests CVSS 4.0MEDIUM 5.3
  • TI-2026-81115 darylldoyle svg-sanitizer CSS Injection and Remote Reference Bypass CVSS 4.0MEDIUM 5.1
See all 11 →

Sources