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Vulnerabilities

Vulnerability · CVE-2026-31790

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.

Published Apr 7, 2026 · catalog updated Jul 24, 2026 · Issue summary: Applications using

Check if you run it

No confirmed exploitation is on record for CVE-2026-31790. EPSS is 1.03%. Act only if a listed version of Issue summary: Applications using is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Issue summary: Applications using).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
1.03%
Remediation
Advisory link
Affected products
cpe openssl/openssl

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe openssl/opensslversion unspecified

How to fix CVE-2026-31790

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-31790. EPSS is 1.03%. Act only if a listed version of Issue summary: Applications using is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-754. EPSS 1.03%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 7, 2026 · NIST NVD

    Detected

    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 wri

  2. Jul 24, 2026 · NIST NVD

    Updated

    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 wri

Sources

  • CVE.orgVulnerability recordCVE-2026-31790

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-31790

    30-day exploitation probability 1.0%

    first.org
  • NIST NVDVulnerability recordCVE-2026-31790

    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 appli

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.