CVE-2026-68453
HighCVSS 7.1Exploitation Probability (EPSS)
Low risk3th percentile - higher than 3% of all known CVEs
Summary
In the Linux kernel, in the s390/zcrypt subsystem, a buffer over-read vulnerability was found in cca_cipher2protkey. User-controlled length fields in CCA token structures were used without proper validation against buffer size and minimum token size, potentially leading to out-of-bounds reads or buffer underruns, causing kernel crashes or memory exposure.
Risk Assessment
An attacker could exploit this to cause a system crash (DoS) or gain access to sensitive kernel memory, posing a serious threat to confidentiality and availability.
Recommendation
Update the Linux kernel to a version containing the fix that adds validation of key buffer size and token length in all cca_check_sec*token() functions and checks for possible underflow in cca_gencipherkey().
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: s390/zcrypt: Fix buffer over-read in cca_cipher2protkey Add validation of both the actual key buffer size and token length fields in all the cca_check_sec*token() functions. Additionally check in cca_gencipherkey() for possible underflow with returned key size. The CCA token structures contain user-controlled len fields that were used in operations without proper validation against both the actual buffer size and minimum token structure size. An attacker could set this field larger than the actual buffer size, leading to reading beyond buffer boundaries. This may result in a kernel crash or exposure of memory via sending this as part of a request down to the crypto card. Also an attacker could have used a very small len value and thus enforce a buffer under-run which may produce similar effects as a over-read. So now a key must - key buf length must be at least sizeof the token struct - the key len field inside the token must fit into the range of sizeof key token struct ... key buf length