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TI-2021-12637 Aliases CVE-2021-33033GHSA-pjv2-crr6-xm2p

The Linux kernel before 5.11.14 has a use-after-free in cipso_v4_genopt in…

Priority LOW 35CWE-416Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 13 fixed, 1 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.

Summary

The Linux kernel before 5.11.14 has a use-after-free in cipso_v4_genopt in net/ipv4/cipso_ipv4.c because the CIPSO and CALIPSO refcounting for the DOI definitions is mishandled, aka CID-ad5d07f4a9cd. This leads to writing an arbitrary value.

Why it matters now

EPSS 0.00571 47th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD
Fix Partial Red Hat: 4 advisoriesRed Hat: 13 fixed, 1 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*2.6.28 to before 4.9.298; 4.10 to before 4.14.226; 4.15 to before 4.19.181; 4.20 to before 5.4.106; 5.5 to before 5.10.24; 5.11 to before 5.11.7VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 2.6.28 to before 4.9.298; 4.10 to before 4.14.226; 4.15 to before 4.19.181; 4.20 to before 5.4.106; 5.5 to before 5.10.24; 5.11 to before 5.11.7 Vulnerable ·Linux

Remediation

Red Hat 4 advisories

  • RHSA-2021:4356 Released 2021-11-09 · Red Hat rating Moderate
    kernel security, bug fix, and enhancement update
    • Red Hat CodeReady Linux Builder (v. 8) kernel-tools-libs-devel-4.18.0-348.el8
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-348.el8, kernel-4.18.0-348.el8, kernel-abi-stablelists-4.18.0-348.el8 +19
  • RHSA-2021:4140 Released 2021-11-09 · Red Hat rating Moderate
    kernel-rt security and bug fix update
    • Red Hat Enterprise Linux Real Time (v. 8) kernel-rt-4.18.0-348.rt7.130.el8, kernel-rt-core-4.18.0-348.rt7.130.el8, kernel-rt-debug-4.18.0-348.rt7.130.el8 +7
    • Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt-4.18.0-348.rt7.130.el8, kernel-rt-core-4.18.0-348.rt7.130.el8, kernel-rt-debug-4.18.0-348.rt7.130.el8 +9
  • RHSA-2021:2725 Released 2021-07-21 · Red Hat rating Important
    kernel security and bug fix update
    • Red Hat Enterprise Linux Client (v. 7) bpftool-3.10.0-1160.36.2.el7, kernel-3.10.0-1160.36.2.el7, kernel-abi-whitelists-3.10.0-1160.36.2.el7 +8
    • Red Hat Enterprise Linux Client Optional (v. 7) kernel-tools-libs-devel-3.10.0-1160.36.2.el7
    • Red Hat Enterprise Linux ComputeNode Optional (v. 7) kernel-tools-libs-devel-3.10.0-1160.36.2.el7
    • Red Hat Enterprise Linux Server (v. 7) bpftool-3.10.0-1160.36.2.el7, kernel-3.10.0-1160.36.2.el7, kernel-abi-whitelists-3.10.0-1160.36.2.el7 +11
    • Red Hat Enterprise Linux Server Optional (v. 7) kernel-debug-devel-3.10.0-1160.36.2.el7, kernel-tools-libs-devel-3.10.0-1160.36.2.el7
    • Red Hat Enterprise Linux Workstation (v. 7) bpftool-3.10.0-1160.36.2.el7, kernel-3.10.0-1160.36.2.el7, kernel-abi-whitelists-3.10.0-1160.36.2.el7 +8
    • Red Hat Enterprise Linux Workstation Optional (v. 7) kernel-tools-libs-devel-3.10.0-1160.36.2.el7
Show 1 more Red Hat advisories
  • RHSA-2021:2726 Released 2021-07-21 · Red Hat rating Important
    kernel-rt security and bug fix update
    • Red Hat Enterprise Linux for Real Time (v. 7) kernel-rt-3.10.0-1160.36.2.rt56.1179.el7, kernel-rt-debug-3.10.0-1160.36.2.rt56.1179.el7, kernel-rt-debug-devel-3.10.0-1160.36.2.rt56.1179.el7 +4
    • Red Hat Enterprise Linux for Real Time for NFV (v. 7) kernel-rt-3.10.0-1160.36.2.rt56.1179.el7, kernel-rt-debug-3.10.0-1160.36.2.rt56.1179.el7, kernel-rt-debug-devel-3.10.0-1160.36.2.rt56.1179.el7 +7

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 7AffectedNo fix planned: Will not fix
Red Hat CodeReady Linux Builder (v. 8)Fixed RHSA-2021:4356
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2021:4356
Red Hat Enterprise Linux Client (v. 7)Fixed RHSA-2021:2725
Red Hat Enterprise Linux Client Optional (v. 7)Fixed RHSA-2021:2725
Red Hat Enterprise Linux ComputeNode Optional (v. 7)Fixed RHSA-2021:2725
Red Hat Enterprise Linux Real Time (v. 8)Fixed RHSA-2021:4140
Red Hat Enterprise Linux Real Time for NFV (v. 8)Fixed RHSA-2021:4140
Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2021:2725
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2021:2725
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2021:2725
Red Hat Enterprise Linux Workstation Optional (v. 7)Fixed RHSA-2021:2725
Red Hat Enterprise Linux for Real Time (v. 7)Fixed RHSA-2021:2726
Red Hat Enterprise Linux for Real Time for NFV (v. 7)Fixed RHSA-2021:2726
Not affected: 2 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-33033
  2. 2026-10-03 Alias added: GHSA-pjv2-crr6-xm2p

References

Exploit 2

Patch 4

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences