CVE-2025-69418: Issue summary: When using the low-level OCB API directly with AES-NI or other hardware-accelerated code paths, inputs whose length is not a multipl...

Description

Issue summary: When using the low-level OCB API directly with AES-NI or other hardware-accelerated code paths, inputs whose length is not a multiple of 16 bytes can leave the final partial block unencrypted and unauthenticated. Impact summary: The trailing 1-15 bytes of a message may be exposed in cleartext on encryption and are not covered by the authentication tag, allowing an attacker to read or tamper with those bytes without detection. The low-level OCB encrypt and decrypt routines in the hardware-accelerated stream path process full 16-byte blocks but do not advance the input/output pointers. The subsequent tail-handling code then operates on the original base pointers, effectively reprocessing the beginning of the buffer while leaving the actual trailing bytes unprocessed. The authentication checksum also excludes the true tail bytes. However, typical OpenSSL consumers using EVP are not affected because the higher-level EVP and provider OCB implementations split inputs so that full blocks and trailing partial blocks are processed in separate calls, avoiding the problematic code path. Additionally, TLS does not use OCB ciphersuites. The vulnerability only affects applications that call the low-level CRYPTO_ocb128_encrypt() or CRYPTO_ocb128_decrypt() functions directly with non-block-aligned lengths in a single call on hardware-accelerated builds. For these reasons the issue was assessed as Low severity. The FIPS modules in 3.6, 3.5, 3.4, 3.3, 3.2, 3.1 and 3.0 are not affected by this issue, as OCB mode is not a FIPS-approved algorithm. OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0 and 1.1.1 are vulnerable to this issue. OpenSSL 1.0.2 is not affected by this issue.

Metrics

CVSS 3.1

4/10

CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS Probability

0.11%

1.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-325

Affected Software

Vendor	Product	Versions
Openssl	Openssl	>= 1.1.1, < 1.1.1ze
Openssl	Openssl	>= 3.0.0, < 3.0.19
Openssl	Openssl	>= 3.3.0, < 3.3.6
Openssl	Openssl	>= 3.4.0, < 3.4.4
Openssl	Openssl	>= 3.5.0, < 3.5.5
Openssl	Openssl	>= 3.6.0, < 3.6.1

References

Timeline

Published: Jan 27, 2026
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2025-69418?

Issue summary: When using the low-level OCB API directly with AES-NI or other hardware-accelerated code paths, inputs whose length is not a multiple of 16 bytes can leave the final partial block unencrypted and unauthenticated. Impact summary: The trailing 1-15 bytes of a message may be exposed in cleartext on encryption and are not covered by the authentication tag, allowing an attacker to read or tamper with those bytes without detection. The low-level OCB encrypt and decrypt routines in the hardware-accelerated stream path process full 16-byte blocks but do not advance the input/output pointers. The subsequent tail-handling code then operates on the original base pointers, effectively reprocessing the beginning of the buffer while leaving the actual trailing bytes unprocessed. The authentication checksum also excludes the true tail bytes. However, typical OpenSSL consumers using EVP are not affected because the higher-level EVP and provider OCB implementations split inputs so that full blocks and trailing partial blocks are processed in separate calls, avoiding the problematic code path. Additionally, TLS does not use OCB ciphersuites. The vulnerability only affects applications that call the low-level CRYPTO_ocb128_encrypt() or CRYPTO_ocb128_decrypt() functions directly with non-block-aligned lengths in a single call on hardware-accelerated builds. For these reasons the issue was assessed as Low severity. The FIPS modules in 3.6, 3.5, 3.4, 3.3, 3.2, 3.1 and 3.0 are not affected by this issue, as OCB mode is not a FIPS-approved algorithm. OpenSSL 3.6, 3.5, 3.4, 3.3, 3.0 and 1.1.1 are vulnerable to this issue. OpenSSL 1.0.2 is not affected by this issue.

How severe is CVE-2025-69418?

CVE-2025-69418 has a CVSS score of 4/10 (MEDIUM severity). The EPSS model estimates a 0.11% probability of exploitation in the next 30 days.

How do I fix CVE-2025-69418?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.