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net/sched: em_text: reject unterminated algo before autoload

Type: advisorySource: Official CVE List1 source record

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

Announced Source revision 1
Original source ↗

CVE-2026-98969

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-98969

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
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Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "d675c989ed2d4ba23dff615330b04371aea83534",
        "lessThan": "00bcc303000bac524d62eed054d77372b38ace0f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "d675c989ed2d4ba23dff615330b04371aea83534",
        "lessThan": "22182f91c6703af6e9832cffe6d22b381031cb5a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "d675c989ed2d4ba23dff615330b04371aea83534",
        "lessThan": "85e5512369d4fe6e5f2c43712d9f9e01d4ae8437",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "d675c989ed2d4ba23dff615330b04371aea83534",
        "lessThan": "b627c6ba20be20334338229b4820baacb9d96826",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "d675c989ed2d4ba23dff615330b04371aea83534",
        "lessThan": "c9728fcf2e7fb4a7a8d08ebd9524c3b02ae1a021",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/sched/em_text.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "2.6.13"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "2.6.13",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.160",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.113",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.57",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.11",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/sched/em_text.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98969

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#52825 · Revision 1
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