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TI-2026-75621 Aliases CVE-2026-98493GHSA-x4fq-3fw2-872x

Out-of-bounds write in Linux kernel ipconfig DHCP options

Priority LOW 22Published · Updated

Key facts

Attack vector
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Privileges required
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User interaction
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Attack complexity
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Impact type
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Confidentiality · integrity · availability
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Fix status
Fixed

No CVSS vector from any source. Fix status from CNA.

Summary

The Linux kernel contains an out-of-bounds write in its ipconfig DHCP option construction, affecting versions from 2.6.36 before the fixed releases. The function ic_dhcp_init_options appends hostname, vendor-class and client-ID options into a fixed 312-byte buffer, and only the client-ID branch checks the remaining space. A 64-byte hostname with a maximum-length vendor class writes past the buffer, and with CONFIG_FORTIFY_SOURCE and panic_on_warn=1 the boot aborts with a panic.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

In the Linux kernel, the following vulnerability has been resolved: net: ipconfig: bound DHCP option construction ic_dhcp_init_options() appends the hostname (option 12), vendor-class (option 60) and client-ID (option 61) options into the fixed 312-byte bootp_pkt.exten[] buffer. Only the client-ID branch checked the remaining space; the hostname and vendor-class writes were unbounded. A 64-byte hostname together with the maximum 252-byte dhcpclass= identifier needs 18 + (2 + 64) + (2 + 252) = 338 of the 312 available bytes even before the terminating END marker, so the vendor-class memcpy runs past the end of exten[]. With CONFIG_FORTIFY_SOURCE this is reported as a field-spanning write and, when the kernel is booted with panic_on_warn=1, aborts boot with a panic. Route the optional options through a common helper that makes sure the option, its 2-byte header and the END marker all fit and drops an option that would not. Configurations with short options keep sending exactly the same bytes as before.

Why it matters now

EPSS 0.00211 11th percentileScored 2026-11-07
Fix Fixed Linux (Linux): 5.10.273, 5.15.224, 6.1.191 +5

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux2.6.36 and later5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.112, 6.18.55, 7.2.9, 7.3Patch availableCNA
  • Linux VendorLinux Affected 2.6.36 and later Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.112, 6.18.55, 7.2.9, 7.3 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*——Linux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions — — ·Linux

Remediation

Update the Linux kernel to 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.112, 6.18.55, 7.2.9 or 7.3, depending on the release branch in use.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA Linux (Linux) Fixed in 5.10.273, 5.15.224, 6.1.191, 6.6.160, 6.12.112, 6.18.55, 7.2.9, 7.3

Vendor assessments

Red Hat

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

Not affected: 7 products
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9
  • Red Hat OpenShift Container Platform 4
  • Red Hat OpenShift Container Platform 5

Timeline

  1. 2026-10-18 Threatist record created from CVE-2026-98493
  2. 2026-10-18 Alias added: GHSA-x4fq-3fw2-872x
  3. 2026-10-19 Fix available: Linux/[email protected] · CNA
  4. 2026-10-21 Affected versions changed · Red Hat
  5. 2026-10-21 CVSS score added · Red Hat
  6. 2026-10-21 Fix available: Linux/Linux@38a6a118260ebfc82d0c653194d616bdfbd236ac, Linux/[email protected] · CNA
  7. 2026-10-21 1 new reference · CNA
  8. 2026-10-30 Fix available: Linux/[email protected], Linux/[email protected], Linux/[email protected] +3 · CNA
  9. 2026-10-30 3 new references · CNA
  10. 2026-11-06 Affected versions changed · Red Hat

References

Other 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-2021-02452 Incorrect authorization in Ubuntu linux kernel 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
See all 21741 →

Sources

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