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TI-2021-21678 Aliases CVE-2021-47013GHSA-3ch6-f277-559q

net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send

Priority MEDIUM 43CWE-416Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 9 fixed, 2 without a fix

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

Summary

In the Linux kernel, the following vulnerability has been resolved: net:emac/emac-mac: Fix a use after free in emac_mac_tx_buf_send In emac_mac_tx_buf_send, it calls emac_tx_fill_tpd(..,skb,..). If some error happens in emac_tx_fill_tpd(), the skb will be freed via dev_kfree_skb(skb) in error branch of emac_tx_fill_tpd(). But the freed skb is still used via skb->len by netdev_sent_queue(,skb->len). As i observed that emac_tx_fill_tpd() haven't modified the value of skb->len, thus my patch assigns skb->len to 'len' before the possible free and use 'len' instead of skb->len later.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0079 56th percentileScored 2026-11-07
Fix Partial Linux (Linux): 4.9.269, 4.14.233, 4.19.191 +5Red Hat: 4 advisoriesRed Hat: 9 fixed, 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
LinuxLinux4.9 and later4.9.269, 4.14.233, 4.19.191, 5.4.119, 5.10.37, 5.11.21, 5.12.4, 5.13Patch availableCNA
  • Linux VendorLinux Affected 4.9 and later Fixed in 4.9.269, 4.14.233, 4.19.191, 5.4.119, 5.10.37, 5.11.21, 5.12.4, 5.13 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*4.9 to before 4.9.269; 4.10 to before 4.14.233; 4.15 to before 4.19.191; 4.20 to before 5.4.119; 5.5 to before 5.10.37; 5.11 to before 5.11.21; 5.12 to before 5.12.4VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.9 to before 4.9.269; 4.10 to before 4.14.233; 4.15 to before 4.19.191; 4.20 to before 5.4.119; 5.5 to before 5.10.37; 5.11 to before 5.11.21; 5.12 to before 5.12.4 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 4.9.269, 4.14.233, 4.19.191, 5.4.119, 5.10.37, 5.11.21, 5.12.4, 5.13

Red Hat 4 advisories

  • RHSA-2024:3810 Released 2024-06-11 · Red Hat rating Moderate
    kernel security and bug fix update
    • Red Hat CodeReady Linux Builder EUS (v.8.8) kernel-tools-libs-devel-4.18.0-477.58.1.el8_8
    • Red Hat Enterprise Linux BaseOS EUS (v.8.8) bpftool-4.18.0-477.58.1.el8_8, kernel-4.18.0-477.58.1.el8_8, kernel-abi-stablelists-4.18.0-477.58.1.el8_8 +19
  • RHSA-2024:3627 Released 2024-06-05 · Red Hat rating Moderate
    kernel-rt security and bug fix update
    • Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.5.1.rt7.346.el8_10, kernel-rt-core-4.18.0-553.5.1.rt7.346.el8_10, kernel-rt-debug-4.18.0-553.5.1.rt7.346.el8_10 +9
    • Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.5.1.rt7.346.el8_10, kernel-rt-core-4.18.0-553.5.1.rt7.346.el8_10, kernel-rt-debug-4.18.0-553.5.1.rt7.346.el8_10 +7
  • RHSA-2024:3618 Released 2024-06-05 · Red Hat rating Moderate
    kernel update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.5.1.el8_10, kernel-4.18.0-553.5.1.el8_10, kernel-abi-stablelists-4.18.0-553.5.1.el8_10 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.5.1.el8_10
Show 1 more Red Hat advisories
  • RHSA-2024:3462 Released 2024-05-29 · Red Hat rating Moderate
    kernel security and bug fix update
    • Red Hat CodeReady Linux Builder EUS (v.8.6) kernel-tools-libs-devel-4.18.0-372.105.1.el8_6
    • Red Hat Enterprise Linux BaseOS EUS (v.8.6) bpftool-4.18.0-372.105.1.el8_6, kernel-4.18.0-372.105.1.el8_6, kernel-abi-stablelists-4.18.0-372.105.1.el8_6 +19
    • Red Hat Virtualization 4 Hypervisor for RHEL 8 kernel-devel-4.18.0-372.105.1.el8_6, perf-4.18.0-372.105.1.el8_6

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
Red Hat CodeReady Linux Builder EUS (v.8.6)Fixed RHSA-2024:3462
Red Hat CodeReady Linux Builder EUS (v.8.8)Fixed RHSA-2024:3810
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2024:3618
Red Hat Enterprise Linux BaseOS EUS (v.8.6)Fixed RHSA-2024:3462
Red Hat Enterprise Linux BaseOS EUS (v.8.8)Fixed RHSA-2024:3810
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2024:3618
Red Hat Enterprise Linux NFV (v. 8)Fixed RHSA-2024:3627
Red Hat Enterprise Linux RT (v. 8)Fixed RHSA-2024:3627
Red Hat Virtualization 4 Hypervisor for RHEL 8Fixed RHSA-2024:3462
Not affected: 1 product
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-47013
  2. 2026-10-03 Alias added: GHSA-3ch6-f277-559q

References

Patch 8

  • 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