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CVE-2026-50721

Libreswan, via the function RSA_authenticate_hash_signature_raw_rsa(), did not correctly verify the length of the authentication hash when the SIG payload of an IKEv1 packet was encoded using PKCS #1 RSA Encryption as per RFC 2313. A remote attacker can use a variation on the Bleichenbacher attack to forge the SIG payload when small public exponents are being used (e.g., e=3), which could lead to impersonation. Additionally, a remote attacker, by encoding a shorter than expected hash in the SIG
Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:c7bf99d323fe6162c85474631250972e6d4efb792da307a20cd50ed28be9156e
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
2

Preserved source conflicts

No provider value was silently selected as the winner.

cvss · 2 assertions

{"metric":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":8.1,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/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:cb5f41d86985e1e204aa0c2325bb2fcda36299511011b7879a1e8082953877b2 · sha256:f9f17c9952700291… · /containers/cna/metrics/1/cvssV3_1

{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"metric_type":"cvssV3_1"}

  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:cb5f41d86985e1e204aa0c2325bb2fcda36299511011b7879a1e8082953877b2 · sha256:f9f17c9952700291… · /containers/cna/metrics/0/cvssV3_1
cwe · 2 assertions

{"cweId":"CWE-347","description":"CWE-347: Improper Verification of Cryptographic Signature","lang":"en","type":"CWE"}

  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:cb5f41d86985e1e204aa0c2325bb2fcda36299511011b7879a1e8082953877b2 · sha256:f9f17c9952700291… · /containers/cna/problemTypes/0/descriptions/0

{"cweId":"CWE-617","description":"CWE-617: Reachable Assertion","lang":"en","type":"CWE"}

  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:cb5f41d86985e1e204aa0c2325bb2fcda36299511011b7879a1e8082953877b2 · sha256:f9f17c9952700291… · /containers/cna/problemTypes/1/descriptions/0

Affected products and versions

1 source assertion
{"collectionURL":"https://github.com/libreswan/libreswan","defaultStatus":"unaffected","packageName":"libreswan","product":"libreswan","programRoutines":[{"name":"RSA_authenticate_hash_signature_raw_rsa"}],"repo":"https://github.com/libreswan/libreswan","vendor":"The Libreswan Project","versions":[{"lessThanOrEqual":"5.3","status":"affected","version":"0","versionType":"semver"},{"status":"unaffected","version":"5.3.1","versionType":"semver"}]}
  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:cb5f41d86985e1e204aa0c2325bb2fcda36299511011b7879a1e8082953877b2 · sha256:f9f17c9952700291… · /containers/cna/affected/0

Provider-owned CVSS observations

2 source assertions
{"metric":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":8.1,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/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:cb5f41d86985e1e204aa0c2325bb2fcda36299511011b7879a1e8082953877b2 · sha256:f9f17c9952700291… · /containers/cna/metrics/1/cvssV3_1
{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"metric_type":"cvssV3_1"}
  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:cb5f41d86985e1e204aa0c2325bb2fcda36299511011b7879a1e8082953877b2 · sha256:f9f17c9952700291… · /containers/cna/metrics/0/cvssV3_1

CWE assertions

2 source assertions
{"cweId":"CWE-347","description":"CWE-347: Improper Verification of Cryptographic Signature","lang":"en","type":"CWE"}
  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:cb5f41d86985e1e204aa0c2325bb2fcda36299511011b7879a1e8082953877b2 · sha256:f9f17c9952700291… · /containers/cna/problemTypes/0/descriptions/0
{"cweId":"CWE-617","description":"CWE-617: Reachable Assertion","lang":"en","type":"CWE"}
  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:cb5f41d86985e1e204aa0c2325bb2fcda36299511011b7879a1e8082953877b2 · sha256:f9f17c9952700291… · /containers/cna/problemTypes/1/descriptions/0

Source references

4 source assertions
{"name":"Libreswan CVE-2026-50721 Patches","tags":["patch"],"url":"https://libreswan.org/security/CVE-2026-50721/"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:cb5f41d86985e1e204aa0c2325bb2fcda36299511011b7879a1e8082953877b2 · sha256:f9f17c9952700291… · /containers/cna/references/1
{"name":"Libreswan Security Advisory CVE-2026-50721","tags":["vendor-advisory"],"url":"https://libreswan.org/security/CVE-2026-50721/CVE-2026-50721.txt"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:cb5f41d86985e1e204aa0c2325bb2fcda36299511011b7879a1e8082953877b2 · sha256:f9f17c9952700291… · /containers/cna/references/0
{"name":"Related: CVE-2026-50722 (IKEv2 variant)","tags":["related"],"url":"https://libreswan.org/security/CVE-2026-50722/CVE-2026-50722.txt"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:cb5f41d86985e1e204aa0c2325bb2fcda36299511011b7879a1e8082953877b2 · sha256:f9f17c9952700291… · /containers/cna/references/2
{"name":"RFC 2313 - PKCS #1: RSA Encryption Version 1.5","tags":["technical-description"],"url":"https://www.rfc-editor.org/rfc/rfc2313"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:cb5f41d86985e1e204aa0c2325bb2fcda36299511011b7879a1e8082953877b2 · sha256:f9f17c9952700291… · /containers/cna/references/3

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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