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TI-2021-02649 Aliases CVE-2021-3715GHSA-gcff-f9p7-hmfg

Use after free in kernel

Priority LOW 34CWE-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: 22 fixed, 3 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

A flaw was found in the "Routing decision" classifier in the Linux kernel's Traffic Control networking subsystem in the way it handled changing of classification filters, leading to a use-after-free condition. This flaw allows unprivileged local users to escalate their privileges on the system. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.

Why it matters now

EPSS 0.00353 29th percentileScored 2026-11-07
Fix Partial Red Hat: 12 advisoriesRed Hat: 22 fixed, 3 without a fix

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
—kernelLinux kernel 5.10—No fix listedCNA
  • kernel Vendor— Affected Linux kernel 5.10 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*3.18 to before 4.4.218; 4.5 to before 4.9.218; 4.10 to before 4.14.175; 4.15 to before 4.19.114; 4.20 to before 5.4.29; 5.5.0 to before 5.5.14VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 3.18 to before 4.4.218; 4.5 to before 4.9.218; 4.10 to before 4.14.175; 4.15 to before 4.19.114; 4.20 to before 5.4.29; 5.5.0 to before 5.5.14 Vulnerable ·Linux

Remediation

Red Hat 12 advisories

  • RHSA-2022:7173 Released 2022-10-25 · Red Hat rating Important
    kpatch-patch security update
    • Red Hat Enterprise Linux Server E4S (v. 7.6) kpatch-patch-3_10_0-957_84_1-1-6.el7, kpatch-patch-3_10_0-957_92_1-1-3.el7, kpatch-patch-3_10_0-957_94_1-1-2.el7 +2
  • RHSA-2021:3477 Released 2021-09-09 · Red Hat rating Important
    RHV-H security update (redhat-virtualization-host) 4.3.18
    • RHEL 7-based RHEV-H for RHEV 4 (build requirements) redhat-virtualization-host-4.3.18-20210903.0.el7_9, redhat-virtualization-host-image-update-4.3.18-20210903.0.el7_9
    • Red Hat Virtualization 4 Hypervisor for RHEL 7 redhat-virtualization-host-4.3.18-20210903.0.el7_9, redhat-virtualization-host-image-update-4.3.18-20210903.0.el7_9
  • RHSA-2021:3446 Released 2021-09-07 · Red Hat rating Important
    kernel security and bug fix update
    • Red Hat CodeReady Linux Builder EUS (v. 8.2) kernel-tools-libs-devel-4.18.0-193.65.2.el8_2
    • Red Hat Enterprise Linux BaseOS EUS (v. 8.2) bpftool-4.18.0-193.65.2.el8_2, kernel-4.18.0-193.65.2.el8_2, kernel-abi-whitelists-4.18.0-193.65.2.el8_2 +19
Show 9 more Red Hat advisories
  • RHSA-2021:3438 Released 2021-09-07 · Red Hat rating Moderate
    kernel security and bug fix update
    • Red Hat Enterprise Linux Client (v. 7) bpftool-3.10.0-1160.42.2.el7, kernel-3.10.0-1160.42.2.el7, kernel-abi-whitelists-3.10.0-1160.42.2.el7 +8
    • Red Hat Enterprise Linux Client Optional (v. 7) kernel-tools-libs-devel-3.10.0-1160.42.2.el7
    • Red Hat Enterprise Linux ComputeNode Optional (v. 7) kernel-tools-libs-devel-3.10.0-1160.42.2.el7
    • Red Hat Enterprise Linux Server (v. 7) bpftool-3.10.0-1160.42.2.el7, kernel-3.10.0-1160.42.2.el7, kernel-abi-whitelists-3.10.0-1160.42.2.el7 +11
    • Red Hat Enterprise Linux Server Optional (v. 7) kernel-debug-devel-3.10.0-1160.42.2.el7, kernel-tools-libs-devel-3.10.0-1160.42.2.el7
    • Red Hat Enterprise Linux Workstation (v. 7) bpftool-3.10.0-1160.42.2.el7, kernel-3.10.0-1160.42.2.el7, kernel-abi-whitelists-3.10.0-1160.42.2.el7 +8
    • Red Hat Enterprise Linux Workstation Optional (v. 7) kernel-tools-libs-devel-3.10.0-1160.42.2.el7
  • RHSA-2021:3441 Released 2021-09-07 · Red Hat rating Moderate
    kpatch-patch security update
    • Red Hat Enterprise Linux Server (v. 7) kpatch-patch-3_10_0-1160-1-9.el7, kpatch-patch-3_10_0-1160_11_1-1-8.el7, kpatch-patch-3_10_0-1160_15_2-1-8.el7 +9
  • RHSA-2021:3444 Released 2021-09-07 · Red Hat rating Important
    kernel security and bug fix update
    • Red Hat CodeReady Linux Builder EUS (v. 8.1) kernel-tools-libs-devel-4.18.0-147.54.2.el8_1
    • Red Hat Enterprise Linux BaseOS EUS (v. 8.1) bpftool-4.18.0-147.54.2.el8_1, kernel-4.18.0-147.54.2.el8_1, kernel-abi-whitelists-4.18.0-147.54.2.el8_1 +19
  • RHSA-2021:3445 Released 2021-09-07 · Red Hat rating Important
    kernel-rt security and bug fix update
    • Red Hat Enterprise Linux Real Time EUS (v. 8.2) kernel-rt-4.18.0-193.65.2.rt13.117.el8_2, kernel-rt-core-4.18.0-193.65.2.rt13.117.el8_2, kernel-rt-debug-4.18.0-193.65.2.rt13.117.el8_2 +7
    • Red Hat Enterprise Linux Real Time for NFV EUS (v. 8.2) kernel-rt-4.18.0-193.65.2.rt13.117.el8_2, kernel-rt-core-4.18.0-193.65.2.rt13.117.el8_2, kernel-rt-debug-4.18.0-193.65.2.rt13.117.el8_2 +9
  • RHSA-2021:3443 Released 2021-09-07 · Red Hat rating Important
    kpatch-patch security update
    • Red Hat Enterprise Linux BaseOS EUS (v. 8.2) kpatch-patch-4_18_0-193_19_1-1-12.el8_2, kpatch-patch-4_18_0-193_28_1-1-10.el8_2, kpatch-patch-4_18_0-193_29_1-1-10.el8_2 +9
  • RHSA-2021:3439 Released 2021-09-07 · Red Hat rating Moderate
    kernel-rt security and bug fix update
    • Red Hat Enterprise Linux for Real Time (v. 7) kernel-rt-3.10.0-1160.42.2.rt56.1182.el7, kernel-rt-debug-3.10.0-1160.42.2.rt56.1182.el7, kernel-rt-debug-devel-3.10.0-1160.42.2.rt56.1182.el7 +4
    • Red Hat Enterprise Linux for Real Time for NFV (v. 7) kernel-rt-3.10.0-1160.42.2.rt56.1182.el7, kernel-rt-debug-3.10.0-1160.42.2.rt56.1182.el7, kernel-rt-debug-devel-3.10.0-1160.42.2.rt56.1182.el7 +7
  • RHSA-2021:3442 Released 2021-09-07 · Red Hat rating Important
    kpatch-patch security update
    • Red Hat Enterprise Linux BaseOS EUS (v. 8.1) kpatch-patch-4_18_0-147_27_1-1-13.el8_1, kpatch-patch-4_18_0-147_32_1-1-11.el8_1, kpatch-patch-4_18_0-147_34_1-1-11.el8_1 +7
  • RHSA-2020:4609 Released 2020-11-04 · Red Hat rating Moderate
    kernel-rt security and bug fix update
    • Red Hat Enterprise Linux Real Time (v. 8) kernel-rt-4.18.0-240.rt7.54.el8, kernel-rt-core-4.18.0-240.rt7.54.el8, kernel-rt-debug-4.18.0-240.rt7.54.el8 +7
    • Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt-4.18.0-240.rt7.54.el8, kernel-rt-core-4.18.0-240.rt7.54.el8, kernel-rt-debug-4.18.0-240.rt7.54.el8 +9
  • RHSA-2020:4431 Released 2020-11-04 · Red Hat rating Moderate
    kernel security, bug fix, and enhancement update
    • Red Hat CodeReady Linux Builder (v. 8) kernel-tools-libs-devel-4.18.0-240.el8
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-240.el8, kernel-4.18.0-240.el8, kernel-abi-whitelists-4.18.0-240.el8 +19

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 5AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
RHEL 7-based RHEV-H for RHEV 4 (build requirements)Fixed RHSA-2021:3477
Red Hat CodeReady Linux Builder (v. 8)Fixed RHSA-2020:4431
Red Hat CodeReady Linux Builder EUS (v. 8.1)Fixed RHSA-2021:3444
Red Hat CodeReady Linux Builder EUS (v. 8.2)Fixed RHSA-2021:3446
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2020:4431
Red Hat Enterprise Linux BaseOS EUS (v. 8.1)Fixed RHSA-2021:3442, RHSA-2021:3444
Red Hat Enterprise Linux BaseOS EUS (v. 8.2)Fixed RHSA-2021:3443, RHSA-2021:3446
Red Hat Enterprise Linux Client (v. 7)Fixed RHSA-2021:3438
Red Hat Enterprise Linux Client Optional (v. 7)Fixed RHSA-2021:3438
Red Hat Enterprise Linux ComputeNode Optional (v. 7)Fixed RHSA-2021:3438
Red Hat Enterprise Linux Real Time (v. 8)Fixed RHSA-2020:4609
Red Hat Enterprise Linux Real Time EUS (v. 8.2)Fixed RHSA-2021:3445
Red Hat Enterprise Linux Real Time for NFV (v. 8)Fixed RHSA-2020:4609
Red Hat Enterprise Linux Real Time for NFV EUS (v. 8.2)Fixed RHSA-2021:3445
Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2021:3438, RHSA-2021:3441
Red Hat Enterprise Linux Server E4S (v. 7.6)Fixed RHSA-2022:7173
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2021:3438
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2021:3438
Red Hat Enterprise Linux Workstation Optional (v. 7)Fixed RHSA-2021:3438
Red Hat Enterprise Linux for Real Time (v. 7)Fixed RHSA-2021:3439
Red Hat Enterprise Linux for Real Time for NFV (v. 7)Fixed RHSA-2021:3439
Red Hat Virtualization 4 Hypervisor for RHEL 7Fixed RHSA-2021:3477
Not affected: 2 products
  • RHEL 7-based RHEV-H for RHEV 4 (build requirements)
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-3715
  2. 2026-10-03 Alias added: GHSA-gcff-f9p7-hmfg

References

Patch 1

  • 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