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CVE-2026-73637

HIGH 7.3

Published 2026-10-01 · Last modified 2026-10-01

Use after free in mod_auth_digest in Apache Software Foundation Apache HTTP Server before 2.4.69 on all platforms allows an unauthenticated remote client to cause authentication state corruption via concurrent Digest authentication requests when AuthDigestNcCheck is enabled or AuthDigestNonceLifetime is set to 0. Users are recommended to upgrade to version 2.4.69, which fixes this issue.

ELEVATED IMPACT

Severe if exploited (CVSS 7.3), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.5%chance of exploitation in 30 days · 40th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

7.3CVSS 3.1 · HIGH

  • ConfidentialityLow
  • IntegrityLow
  • AvailabilityLow

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ 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-2026-73637/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-2026-73637/poc.json

Affected

Vendors Apache Software Foundation Apache

Products Apache Http Server Http Server

Weakness (CWE)

  • CWE-416: Use After Free

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Known Affected Software Configurations

VendorProductVersion range
ApacheHttp Server≥ 2.4.0 and < 2.4.69

All CVSS metrics

  • HIGH 7.3 v3.1 · ADP Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
  • HIGH 7.3 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

References

Advisories

Sources: NVD · CVE.org · EPSS