Read the docs
TI-2021-21640 Aliases CVE-2021-46974GHSA-78xq-q56p-fpwx

bpf: Fix masking negation logic upon negative dst register

Priority LOW 31Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · None · High
Fix status
Partial Red Hat: 2 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix masking negation logic upon negative dst register The negation logic for the case where the off_reg is sitting in the dst register is not correct given then we cannot just invert the add to a sub or vice versa. As a fix, perform the final bitwise and-op unconditionally into AX from the off_reg, then move the pointer from the src to dst and finally use AX as the source for the original pointer arithmetic operation such that the inversion yields a correct result. The single non-AX mov in between is possible given constant blinding is retaining it as it's not an immediate based operation.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00249 16th percentileScored 2026-11-07
Fix Partial Linux (Linux): 4.14.233, 4.19.190, 4.21 +5Red Hat: 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux4.14.113 to before 4.14.233; 4.19.19 to before 4.19.190; 4.20.6 to before 4.214.14.233, 4.19.190, 4.21Patch availableCNA
LinuxLinux5.0 and later4.14.233, 4.19.190, 5.4.117, 5.10.35, 5.11.19, 5.12.2, 5.13Patch availableCNA
  • Linux VendorLinux Affected 4.14.113 to before 4.14.233; 4.19.19 to before 4.19.190; 4.20.6 to before 4.21 Fixed in 4.14.233, 4.19.190, 4.21 Patch available CNA
  • Linux VendorLinux Affected 5.0 and later Fixed in 4.14.233, 4.19.190, 5.4.117, 5.10.35, 5.11.19, 5.12.2, 5.13 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*4.14.113 to before 4.14.233; 4.19.19 to before 4.19.190; 5.0 to before 5.4.117; 5.5 to before 5.10.35; 5.11 to before 5.11.19; 5.12 to before 5.12.2VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.14.113 to before 4.14.233; 4.19.19 to before 4.19.190; 5.0 to before 5.4.117; 5.5 to before 5.10.35; 5.11 to before 5.11.19; 5.12 to before 5.12.2 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 4.14.233, 4.19.190, 4.21
  • Fix · CNA Linux (Linux) Fixed in 4.14.233, 4.19.190, 5.4.117, 5.10.35, 5.11.19, 5.12.2, 5.13

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
Not affected: 2 products
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-46974
  2. 2026-10-03 Alias added: GHSA-78xq-q56p-fpwx

References

Patch 7

  • 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