CVE-2026-23243

NameCVE-2026-23243
DescriptionIn the Linux kernel, the following vulnerability has been resolved: RDMA/umad: Reject negative data_len in ib_umad_write ib_umad_write computes data_len from user-controlled count and the MAD header sizes. With a mismatched user MAD header size and RMPP header length, data_len can become negative and reach ib_create_send_mad(). This can make the padding calculation exceed the segment size and trigger an out-of-bounds memset in alloc_send_rmpp_list(). Add an explicit check to reject negative data_len before creating the send buffer. KASAN splat: [ 211.363464] BUG: KASAN: slab-out-of-bounds in ib_create_send_mad+0xa01/0x11b0 [ 211.364077] Write of size 220 at addr ffff88800c3fa1f8 by task spray_thread/102 [ 211.365867] ib_create_send_mad+0xa01/0x11b0 [ 211.365887] ib_umad_write+0x853/0x1c80
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-4561-1, DSA-6238-1, DSA-6243-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)bullseye5.10.223-1vulnerable
bullseye (security)5.10.251-5vulnerable
bookworm6.1.170-3fixed
bookworm (security)6.1.172-1fixed
trixie6.12.86-1fixed
trixie (security)6.12.88-1fixed
forky, sid7.0.7-1fixed
linux-6.1 (PTS)bullseye (security)6.1.172-1~deb11u1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcebookworm6.1.170-1DSA-6243-1
linuxsourcetrixie6.12.85-1DSA-6238-1
linuxsource(unstable)6.18.14-1
linux-6.1sourcebullseye6.1.170-1~deb11u1DLA-4561-1

Notes

https://git.kernel.org/linus/5551b02fdbfd85a325bb857f3a8f9c9f33397ed2 (7.0-rc1)

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