CVE-2026-89879

Description

In the Linux kernel, the following vulnerability has been resolved: media: s2255: bound JPEG frame size before copying into the buffer s2255_fillbuff() memcpy()s vc->jpg_size bytes of a captured JPEG/MJPEG frame into the vb2 plane. vc->jpg_size is taken verbatim from the S2255_MARKER_FRAME header the device sends (pdword[4] in save_frame()) and, unlike the frame payload length just above it, is never bounded: payload = le32_to_cpu(pdword[3]); if (payload > vc->req_image_size) /* payload is checked ... */ return -EINVAL; vc->pkt_size = payload; vc->jpg_size = le32_to_cpu(pdword[4]); /* ... jpg_size is not */ A malicious or malfunctioning device can therefore report a jpg_size larger than the destination vb2 plane, and the memcpy() writes past it. jpg_size is a signed int, so a value with the top bit set also turns into a huge length. Reject a frame whose jpg_size is negative or exceeds the plane size before copying it.

References

• https://git.kernel.org/stable/c/2542516a147bfad740e7e411c251b639fad260ff
• https://git.kernel.org/stable/c/32a595dd3e8634544e5cfbc47f906dff3d3c1ef8
• https://git.kernel.org/stable/c/4b6f7bccc6559ae5c54573c284fe76eafc9989b2
• https://git.kernel.org/stable/c/68d664f1b4efe525e99154b7058fcb0378bdaff7
• https://git.kernel.org/stable/c/79f58f900dd221ab04ea74bf4eaf79fa3b0fcc77