cbcvebase.
CVE-2026-31790
published 2026-04-07

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…

PriorityP348high7.5CVSS 3.1
AVNACLPRNUINSUCHINAN
EPSS
1.20%
65.0th percentile
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

11 ranges
VendorProductVersion rangeFixed in
debianopenssl< openssl 3.0.19-1~deb12u2 (bookworm)openssl 3.0.19-1~deb12u2 (bookworm)
msrcazl3_openssl_3.3.5-4_on_azure_linux_3.0
opensslopenssl>= 0 < 3.5.6-r03.5.6-r0
opensslopenssl>= 0 < 3.5.6-r03.5.6-r0
opensslopenssl>= 0 < 3.0.19-1~deb12u23.0.19-1~deb12u2
opensslopenssl>= 0 < 3.5.5-1~deb13u23.5.5-1~deb13u2
opensslopenssl>= 3.0.0 < 3.0.203.0.20
opensslopenssl>= 3.3.0 < 3.3.73.3.7
opensslopenssl>= 3.4.0 < 3.4.53.4.5
opensslopenssl>= 3.5.0 < 3.5.63.5.6
opensslopenssl>= 3.6.0 < 3.6.23.6.2

CVSS provenance

nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
osv7.5HIGH
vendor_debian7.5HIGH
vendor_redhat7.5HIGH
vendor_ubuntu7.5HIGH
vendor_msrc6.5MEDIUM
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