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Review reviewHigh

CVE-2020-36791

Linux Linux, linux kernel

In the Linux kernel, the following vulnerability has been resolved: net_sched: keep alloc_hash updated after hash allocation In commit 599be01ee567 ("net_sched: fix an OOB access in cls_tcindex") I moved cp->hash calculation before the first tcindex_alloc_perfect_hash(), but cp->alloc_hash is left untouched. This difference could lead to another out of bound access. cp->alloc_hash should always be the size allocated, we should update it after this tcindex_alloc_perfect_hash().

CVSS
7.1
EPSS
-
- percentile
CISA KEV
Not listed
Published
2025.05.07
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 7.1

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: net_sched: keep alloc_hash updated after hash allocation In commit 599be01ee567 ("net_sched: fix an OOB access in cls_tcindex") I moved cp->hash calculation before the first tcindex_alloc_perfect_hash(), but cp->alloc_hash is left untouched. This difference could lead to another out of bound access. cp->alloc_hash should always be the size allocated, we should update it after this tcindex_alloc_perfect_hash().

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= 73c29d2f6f8ae731b1e09051b69ed3ba2319482b < d6cdc5bb19b595486fb2e6661e5138d73a57f454, >= b974ac51f5834a729de252fc5c1c9de9efd79b45 < c4453d2833671e3a9f6bd52f0f581056c3736386, >= 6cb448ee493c8a514c9afa0c346f3f5b3227de85 < 9f8b6c44be178c2498a00b270872a6e30e7c8266, >= 478c4b2ffd44e5186c7e22ae7c38a86a5b9cfde5 < 557d015ffb27b672e24e6ad141fd887783871dc2, >= dd8142a6fa5270783d415292ec8169f4ea2a5468 < d23faf32e577922b6da20bf3740625c1105381bf, >= 2c66ff8d08f81bcf8e8cb22e31e39c051b15336a < bd3ee8fb6371b45c71c9345cc359b94da2ddefa9, >= 599be01ee567b61f4471ee8078870847d0a11e8e < 0d1c3530e1bd38382edef72591b78e877e0edcd3, >= 4.4.214 < 4.4.218, >= 4.9.214 < 4.9.218, >= 4.14.171 < 4.14.175, >= 4.19.103 < 4.19.114, >= 5.4.19 < 5.4.29, >= 5.5.3 < 5.5.14, 5.6
Fixed versions
4.4.218, 4.9.218, 4.14.175, 4.19.114, 5.4.29, 5.5.14

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
CWE
CWE-125