NULL pointer dereference in Openssl
CVE-2025-11187
Issue summary: PBMAC1 parameters in PKCS#12 files are missing validation which can trigger a stack-based buffer overflow, invalid pointer or NULL pointer dereference during MAC verification. Impact summary: The stack buffer overflow or NULL pointer dereference may cause a crash leading to Denial of Service for an application that parses untrusted PKCS#12 files. The buffer overflow may also potentially enable code execution depending on platform mitigations. When verifying a PKCS#12 file that uses PBMAC1 for the MAC, the PBKDF2 salt and keylength parameters from the file are used without validation. If the value of keylength exceeds the size of the fixed stack buffer used for the derived key (64 bytes), the key derivation will overflow the buffer. The overflow length is attacker-controlled. Also, if the salt parameter is not an OCTET STRING type this can lead to invalid or NULL pointer dereference. Exploiting this issue requires a user or application to process a maliciously crafted PKCS#12 file. It is uncommon to accept untrusted PKCS#12 files in applications as they are usually used to store private keys which are trusted by definition. For this reason the issue was assessed as Moderate severity. The FIPS modules in 3.6, 3.5 and 3.4 are not affected by this issue, as PKCS#12 processing is outside the OpenSSL FIPS module boundary. OpenSSL 3.6, 3.5 and 3.4 are vulnerable to this issue. OpenSSL 3.3, 3.0, 1.1.1 and 1.0.2 are not affected by this issue as they do not support PBMAC1 in PKCS#12.
EPSS: 0.045 (90.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:H.
Affected products
- Openssl — versions 3.6.0, 3.5.0, 3.4.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- openssl-security@openssl.org (vendor-advisory, Vendor Advisory)
- openssl-security@openssl.org (Patch, patch)
- openssl-security@openssl.org (Patch, patch)
- openssl-security@openssl.org (Patch, patch)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0
Frequently asked questions
- What is CVE-2025-11187?
- CVE-2025-11187 is a medium-severity vulnerability in Openssl, classified under NULL Pointer Dereference. CVSS score: 6.1/10. Published 2026-01-27.
- How severe is CVE-2025-11187?
- Medium severity. CVSS v3 base score is 6.1 out of 10.
- Is CVE-2025-11187 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.