net/sched: em_text: reject unterminated algo before autoload
Summary
| CVE | CVE-2026-98969 |
|---|
| State | PUBLISHED |
|---|
| Assigner | Linux |
|---|
| Source Priority | CVE Program / NVD first with legacy fallback |
|---|
| Published | 2026-10-23 13:17:18 UTC |
|---|
| Updated | 2026-10-23 13:17:18 UTC |
|---|
| Description | In the Linux kernel, the following vulnerability has been resolved:
net/sched: em_text: reject unterminated algo before autoload
This is a follow-up to commit 9c572a83037a ("net/sched: fix potential
stack infoleak in em_text_dump()"), which zero-initialised the dump-side
struct. Sashiko pointed at a pre-existing bug that exposed the change-side
input-validation gap open.
em_text_change() casts the raw netlink attribute payload to struct
tcf_em_text and passes conf->algo, a 16-byte array with no enforced NUL
terminator, to textsearch_prepare(). On the TS_AUTOLOAD retry
textsearch_prepare() calls request_module("ts_%s", algo); vsnprintf()
walks %s until it finds a NUL, so an algo[] with no NUL reads past the
array into the adjacent struct fields and payload and feeds those bytes
to the usermode helper command line. This is an out-of-bounds read and
a kernel memory disclosure.
Reject the attribute when no NUL exists within TC_EM_TEXT_ALGOSIZ bytes,
matching the check xt_string has had since 3ab720881b6e.
Conditions to recreate the bug:
- CAP_NET_ADMIN on the target netns (namespace-local via unshare -Urn
is enough)
- install clsact on an interface, then add a basic filter with one text
ematch whose algo[] is 16 bytes with no NUL (e.g. "A"*16) and
pattern_len at least 1
- the add fails with -ENOENT and the kernel invokes modprobe with a
module name made of "ts_" plus the 16 bytes and the adjacent payload |
|---|
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|
| CNA |
Linux |
Linux |
affected d675c989ed2d4ba23dff615330b04371aea83534 00bcc303000bac524d62eed054d77372b38ace0f git |
Not specified |
| CNA |
Linux |
Linux |
affected d675c989ed2d4ba23dff615330b04371aea83534 22182f91c6703af6e9832cffe6d22b381031cb5a git |
Not specified |
| CNA |
Linux |
Linux |
affected d675c989ed2d4ba23dff615330b04371aea83534 85e5512369d4fe6e5f2c43712d9f9e01d4ae8437 git |
Not specified |
| CNA |
Linux |
Linux |
affected d675c989ed2d4ba23dff615330b04371aea83534 b627c6ba20be20334338229b4820baacb9d96826 git |
Not specified |
| CNA |
Linux |
Linux |
affected d675c989ed2d4ba23dff615330b04371aea83534 c9728fcf2e7fb4a7a8d08ebd9524c3b02ae1a021 git |
Not specified |
| CNA |
Linux |
Linux |
affected 2.6.13 |
Not specified |
| CNA |
Linux |
Linux |
unaffected 2.6.13 semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.6.160 6.6.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.12.113 6.12.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.18.57 6.18.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.2.11 7.2.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.3 * original_commit_for_fix |
Not specified |
References
| Reference | Source | Link | Tags |
|---|
| git.kernel.org/stable/c/00bcc303000bac524d62eed054d77372b38ace0f |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/85e5512369d4fe6e5f2c43712d9f9e01d4ae8437 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/b627c6ba20be20334338229b4820baacb9d96826 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/22182f91c6703af6e9832cffe6d22b381031cb5a |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/c9728fcf2e7fb4a7a8d08ebd9524c3b02ae1a021 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| CVE Program record |
CVE.ORG |
www.cve.org |
canonical |
| NVD vulnerability detail |
NVD |
nvd.nist.gov |
canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.