CVE-2025-71113
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
In the Linux kernel's af_alg crypto mechanism, a vulnerability was found due to missing zero-initialization of memory allocated via sock_kmalloc(). Uninitialized context and request structures can lead to use of garbage values; specifically, the newly added 'inflight' field causes random -EBUSY errors in multi-threaded AIO requests.
Risk Assessment
The organization faces instability in applications using kernel crypto interfaces (e.g., algif_kpp, algif_akcipher), manifesting as random request rejections (EBUSY), potentially causing service disruptions or data processing errors.
Recommendation
Immediately update the Linux kernel to a version containing the fix that zero-initializes memory allocated via sock_kmalloc() in the af_alg context. A system reboot is required after the update.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: crypto: af_alg - zero initialize memory allocated via sock_kmalloc Several crypto user API contexts and requests allocated with sock_kmalloc() were left uninitialized, relying on callers to set fields explicitly. This resulted in the use of uninitialized data in certain error paths or when new fields are added in the future. The ACVP patches also contain two user-space interface files: algif_kpp.c and algif_akcipher.c. These too rely on proper initialization of their context structures. A particular issue has been observed with the newly added 'inflight' variable introduced in af_alg_ctx by commit: 67b164a871af ("crypto: af_alg - Disallow multiple in-flight AIO requests") Because the context is not memset to zero after allocation, the inflight variable has contained garbage values. As a result, af_alg_alloc_areq() has incorrectly returned -EBUSY randomly when the garbage value was interpreted as true: https://github.com/gregkh/linux/blame/master/crypto/af_alg.c#L1209 The check directly tests ctx->inflight without explicitly comparing against true/false. Since inflight is only ever set to true or false later, an uninitialized value has triggered -EBUSY failures. Zero-initializing memory allocated with sock_kmalloc() ensures inflight and other fields start in a known state, removing random issues caused by uninitialized data.