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7.5
CVE-2026-31790EXPLOITEDPATCHED
openssl · openssl

Incorrect Failure Handling in RSA KEM RSASVE Encapsulation

Description

Issue summary: Applications using RSASVE key encapsulation to establish a secret encryption key can send contents of an uninitialized memory buffer to a malicious peer. Impact summary: The uninitialized buffer might contain sensitive data from the previous execution of the application process which leads to sensitive data leakage to an attacker. RSA_public_encrypt() returns the number of bytes written on success and -1 on error. The affected code tests only whether the return value is non-zero. As a result, if RSA encryption fails, encapsulation can still return success to the caller, set the output lengths, and leave the caller to use the contents of the ciphertext buffer as if a valid KEM ciphertext had been produced. If applications use EVP_PKEY_encapsulate() with RSA/RSASVE on an attacker-supplied invalid RSA public key without first validating that key, then this may cause stale or uninitialized contents of the caller-provided ciphertext buffer to be disclosed to the attacker in place of the KEM ciphertext. As a workaround calling EVP_PKEY_public_check() or EVP_PKEY_public_check_quick() before EVP_PKEY_encapsulate() will mitigate the issue. The FIPS modules in 3.6, 3.5, 3.4, 3.3, 3.1 and 3.0 are affected by this issue.

Affected Products

VendorProductVersions
opensslopenssl3.6.0, 3.5.0, 3.4.0, 3.3.0, 3.0.0, 3.6.0 - < 3.6.2, 3.5.0 - < 3.5.6, 3.4.0 - < 3.4.5, 3.3.0 - < 3.3.7, 3.0.0 - < 3.0.20

References

  • https://openssl-library.org/news/secadv/20260407.txt(vendor-advisory)
  • https://github.com/openssl/openssl/commit/abd8b2eec7e3f3fda60ecfb68498b246b52af482(patch)
  • https://github.com/openssl/openssl/commit/001e01db3e996e13ffc72386fe79d03a6683b5ac(patch)
  • https://github.com/openssl/openssl/commit/d5f8e71cd0a54e961d0c3b174348f8308486f790(patch)
  • https://github.com/openssl/openssl/commit/b922e24e5b23ffb9cb9e14cadff23d91e9f7e406(patch)
  • https://github.com/openssl/openssl/commit/eed200f58cd8645ed77e46b7e9f764e284df379e(patch)

Related News (9 articles)

Tier D
Help Net Security5h ago
Week in review: Windows zero-day exploit leaked, Patch Tuesday forecast
→ No new info (linked only)
Tier A
Microsoft MSRC3d ago
CVE-2026-31790 Incorrect Failure Handling in RSA KEM RSASVE Encapsulation
→ No new info (linked only)
Tier B
CCCS Canada3d ago
OpenSSL security advisory (AV26-329)
→ No new info (linked only)
Tier D
SecurityWeek3d ago
Data Leakage Vulnerability Patched in OpenSSL
→ No new info (linked only)
Tier B
BSI Advisories4d ago
[NEU] [mittel] OpenSSL: Mehrere Schwachstellen
→ No new info (linked only)
Tier D
Help Net Security4d ago
OpenSSL 3.6.2 lands with eight CVE fixes
→ No new info (linked only)
Tier B
CERT-FR4d ago
Multiples vulnérabilités dans OpenSSL (08 avril 2026)
→ No new info (linked only)
Tier C
VulDB4d ago
CVE-2026-31790 | OpenSSL up to 3.0.19/3.3.6/3.4.4/3.5.5/3.6.1 RSA KEM RSASVE Encapsulation RSA_public_encrypt uninitialized pointer
→ No new info (linked only)
Tier C
oss-security4d ago
OpenSSL Security Advisory
→ No new info (linked only)
CVSS 3.17.5 MEDIUM
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CISA KEV❌ No
Actively exploited✅ Yes
Patch available
3.6.23.5.63.4.53.3.73.0.20
CWECWE-754
PublishedApr 7, 2026
Last enriched4h agov4
Tags
CVE-2026-31790denial of serviceinformation disclosuremultiple vulnerabilitiessecurity advisoryopensslCVE-2026-34197CVE-2026-2673CVE-2026-34078
Trending Score85
Source articles10
Independent8
Info Completeness10/14
Missing: epss, kev, iocs, mitre_attack

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Verification

State: unverified
Confidence: 0%

Vulnerability Timeline

CVE Published
Apr 7, 2026
Discovered by ZDM
Apr 7, 2026
Updated: cweIds, tags
Apr 8, 2026
Actively Exploited
Apr 8, 2026
Exploit Available
Apr 8, 2026
Patch Available
Apr 8, 2026
Updated: severity, exploitAvailable, activelyExploited
Apr 8, 2026
Updated: tags
Apr 12, 2026

Version History

v4
Last enriched 4h ago
v4Tier D4h ago

Added new CVE IDs: CVE-2026-34197, CVE-2026-2673, and CVE-2026-34078 to the tags.

tags
via Help Net Security
v3Tier D3d ago

Updated severity to MEDIUM, marked exploit availability and active exploitation as true, and added CVE-2026-31790 to tags.

severityexploitAvailableactivelyExploited
via SecurityWeek
v2Tier D4d ago

Updated severity to MEDIUM, added new patch version 3.6.2, and included new CVE ID CVE-2026-31790.

cweIdstags
via Help Net Security
v14d ago

Initial creation