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CVE-2026-56766

Hydra through 9.7, fixed in commit 9cc84c2, contains a stack buffer overflow in NTLM authentication across SMTP, POP3, IMAP, NNTP, HTTP, HTTP-Proxy, and HTTP-Proxy-Urlenum modules when processing malicious NTLM Type-2 challenges. A malicious server can send a crafted NTLM Type-2 challenge with an excessively long domain string, causing base64-encoded response data to overflow a 500-byte stack buffer by 18 to 330 bytes, enabling remote code execution on systems without stack protection.
Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:33e33a7fbce86c50997e98470be2bbb18ff5eeb2bb0e948c551124eff61d432f
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
1

Preserved source conflicts

No provider value was silently selected as the winner.

cvss · 2 assertions

{"metric":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":8.6,"baseSeverity":"HIGH","exploitMaturity":"NOT_DEFINED","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"ACTIVE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact"…

  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:7662b3f8377715f1531ee43912246b956d8e39ee014f91300bb9276b727bc929 · sha256:ee1233c69a24046e… · /containers/cna/metrics/0/cvssV4_0

{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":8.8,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","version":"3.1"},"metric_type":"cvssV3_1"}

  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:7662b3f8377715f1531ee43912246b956d8e39ee014f91300bb9276b727bc929 · sha256:ee1233c69a24046e… · /containers/cna/metrics/1/cvssV3_1

Affected products and versions

1 source assertion
{"defaultStatus":"unaffected","packageURL":"pkg:github/vanhauser-thc/thc-hydra","product":"thc-hydra","repo":"https://github.com/vanhauser-thc/thc-hydra","vendor":"vanhauser-thc","versions":[{"lessThanOrEqual":"9.7","status":"affected","version":"0","versionType":"custom"},{"status":"unaffected","version":"9cc84c20e75f5fef6bb1790bb9ada2afad2204e2","versionType":"git"}]}
  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:7662b3f8377715f1531ee43912246b956d8e39ee014f91300bb9276b727bc929 · sha256:ee1233c69a24046e… · /containers/cna/affected/0

Provider-owned CVSS observations

2 source assertions
{"metric":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":8.6,"baseSeverity":"HIGH","exploitMaturity":"NOT_DEFINED","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"ACTIVE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact"…
  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:7662b3f8377715f1531ee43912246b956d8e39ee014f91300bb9276b727bc929 · sha256:ee1233c69a24046e… · /containers/cna/metrics/0/cvssV4_0
{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":8.8,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","version":"3.1"},"metric_type":"cvssV3_1"}
  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:7662b3f8377715f1531ee43912246b956d8e39ee014f91300bb9276b727bc929 · sha256:ee1233c69a24046e… · /containers/cna/metrics/1/cvssV3_1

CWE assertions

1 source assertion
{"cweId":"CWE-121","description":"Stack-based Buffer Overflow","lang":"en","type":"CWE"}
  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:7662b3f8377715f1531ee43912246b956d8e39ee014f91300bb9276b727bc929 · sha256:ee1233c69a24046e… · /containers/cna/problemTypes/0/descriptions/0

Source references

2 source assertions
{"name":"Patch Commit","tags":["patch"],"url":"https://github.com/vanhauser-thc/thc-hydra/commit/9cc84c20e75f5fef6bb1790bb9ada2afad2204e2"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:7662b3f8377715f1531ee43912246b956d8e39ee014f91300bb9276b727bc929 · sha256:ee1233c69a24046e… · /containers/cna/references/0
{"tags":["third-party-advisory"],"url":"https://www.vulncheck.com/advisories/hydra-stack-buffer-overflow-in-ntlm-authentication-handler"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:7662b3f8377715f1531ee43912246b956d8e39ee014f91300bb9276b727bc929 · sha256:ee1233c69a24046e… · /containers/cna/references/1

Attribution and limitations

  • CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →

Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.

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