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TI-2026-45549 Aliases CVE-2026-63984GHSA-6hh9-w4p2-c5qm

ipv6: rpl: fix hdrlen overflow in ipv6_rpl_srh_decompress()

Priority MEDIUM 49CWE-190Published · 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: 30 fixed, 2 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-190 and the CVSS impact.

Summary

In the Linux kernel, the following vulnerability has been resolved: ipv6: rpl: fix hdrlen overflow in ipv6_rpl_srh_decompress() ipv6_rpl_srh_decompress() computes: outhdr->hdrlen = (((n + 1) * sizeof(struct in6_addr)) >> 3); hdrlen is __u8. For n >= 127 the result exceeds 255 and silently truncates. With n=127 (cmpri=15, cmpre=15, pad=0, hdrlen=16): (128 * 16) >> 3 = 256, truncated to 0 as __u8 The caller in ipv6_rpl_srh_rcv() then places the compressed header at buf + ((ohdr->hdrlen + 1) << 3). With hdrlen=0 this is buf + 8, but the decompressed region occupies buf[0..2055] (8-byte header plus 128 full addresses). The compressed header overlaps the decompressed data, and ipv6_rpl_srh_compress() writes into this overlap, corrupting the routing header of the forwarded packet. The existing guard at exthdrs.c:546 checks (n + 1) > 255, which prevents n+1 from overflowing unsigned char (the segments_left field), but does not prevent the computed hdrlen from overflowing __u8. n=127 passes because 128 <= 255, yet hdrlen=256 does not fit. Tighten the bound to (n + 1) > 127. This caps n at 126, giving hdrlen = (127 * 16) >> 3 = 254, which fits in __u8. The compressed header then lands at buf + ((254 + 1) << 3) = buf + 2040, exactly past the decompressed region (buf[0..2039]). No overlap. 127 segments is well beyond any realistic RPL deployment.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00514 44th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.259, 5.15.210, 6.1.176 +5Red Hat: 7 advisoriesRed Hat: 30 fixed, 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

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

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux5.7 and later5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12, 7.1Patch availableCNA
  • Linux VendorLinux Affected 5.7 and later Fixed in 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12, 7.1 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

  • Fix · CNA Linux (Linux) Fixed in 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, 6.18.35, 7.0.12, 7.1

Red Hat 7 advisories

  • RHSA-2026:93047 Released 2026-10-30 · Red Hat rating Important
    kernel-rt security, bug fix, and enhancement update
    • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt-5.14.0-284.200.1.rt14.485.el9_2, kernel-rt-core-5.14.0-284.200.1.rt14.485.el9_2, kernel-rt-debug-5.14.0-284.200.1.rt14.485.el9_2 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt-5.14.0-284.200.1.rt14.485.el9_2, kernel-rt-core-5.14.0-284.200.1.rt14.485.el9_2, kernel-rt-debug-5.14.0-284.200.1.rt14.485.el9_2 +11
  • RHSA-2026:92993 Released 2026-10-30 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream E4S (v.9.2) kernel-64k-debug-devel-5.14.0-284.200.1.el9_2, kernel-64k-debug-devel-matched-5.14.0-284.200.1.el9_2, kernel-64k-devel-5.14.0-284.200.1.el9_2 +10
    • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool-7.0.0-284.200.1.el9_2, kernel-5.14.0-284.200.1.el9_2, kernel-64k-5.14.0-284.200.1.el9_2 +29
  • RHSA-2026:83707 Released 2026-10-16 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) kernel-64k-debug-devel-6.12.0-55.111.1.el10_0, kernel-64k-debug-devel-matched-6.12.0-55.111.1.el10_0, kernel-64k-devel-6.12.0-55.111.1.el10_0 +12
    • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel-6.12.0-55.111.1.el10_0, kernel-64k-6.12.0-55.111.1.el10_0, kernel-64k-core-6.12.0-55.111.1.el10_0 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) kernel-tools-libs-devel-6.12.0-55.111.1.el10_0, libperf-6.12.0-55.111.1.el10_0
    • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt-6.12.0-55.111.1.el10_0, kernel-rt-64k-6.12.0-55.111.1.el10_0, kernel-rt-64k-core-6.12.0-55.111.1.el10_0 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt-6.12.0-55.111.1.el10_0, kernel-rt-core-6.12.0-55.111.1.el10_0, kernel-rt-debug-6.12.0-55.111.1.el10_0 +11
Show 4 more Red Hat advisories
  • RHSA-2026:76739 Released 2026-10-08 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-687.55.1.el9_8, kernel-64k-debug-devel-matched-5.14.0-687.55.1.el9_8, kernel-64k-devel-5.14.0-687.55.1.el9_8 +12
    • Red Hat Enterprise Linux BaseOS (v. 9) kernel-5.14.0-687.55.1.el9_8, kernel-64k-5.14.0-687.55.1.el9_8, kernel-64k-core-5.14.0-687.55.1.el9_8 +28
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) kernel-tools-libs-devel-5.14.0-687.55.1.el9_8, libperf-5.14.0-687.55.1.el9_8
    • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt-5.14.0-687.55.1.el9_8, kernel-rt-64k-5.14.0-687.55.1.el9_8, kernel-rt-64k-core-5.14.0-687.55.1.el9_8 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt-5.14.0-687.55.1.el9_8, kernel-rt-core-5.14.0-687.55.1.el9_8, kernel-rt-debug-5.14.0-687.55.1.el9_8 +9
  • RHSA-2026:77219 Released 2026-10-08 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • Red Hat CodeReady Linux Builder EUS (v.9.6) kernel-tools-libs-devel-5.14.0-570.147.1.el9_6, libperf-5.14.0-570.147.1.el9_6
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) kernel-64k-debug-devel-5.14.0-570.147.1.el9_6, kernel-64k-debug-devel-matched-5.14.0-570.147.1.el9_6, kernel-64k-devel-5.14.0-570.147.1.el9_6 +12
    • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel-5.14.0-570.147.1.el9_6, kernel-64k-5.14.0-570.147.1.el9_6, kernel-64k-core-5.14.0-570.147.1.el9_6 +28
    • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt-5.14.0-570.147.1.el9_6, kernel-rt-64k-5.14.0-570.147.1.el9_6, kernel-rt-64k-core-5.14.0-570.147.1.el9_6 +21
    • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt-5.14.0-570.147.1.el9_6, kernel-rt-core-5.14.0-570.147.1.el9_6, kernel-rt-debug-5.14.0-570.147.1.el9_6 +11
  • RHSA-2026:76738 Released 2026-10-08 · Red Hat rating Important
    kernel security, bug fix, and enhancement update
    • 10Base-SMTV kernel-modules-internal-6.12.0-211.63.1.el10_2
    • Red Hat Enterprise Linux AppStream (v. 10) kernel-64k-debug-devel-6.12.0-211.63.1.el10_2, kernel-64k-debug-devel-matched-6.12.0-211.63.1.el10_2, kernel-64k-devel-6.12.0-211.63.1.el10_2 +12
    • Red Hat Enterprise Linux BaseOS (v. 10) kernel-6.12.0-211.63.1.el10_2, kernel-64k-6.12.0-211.63.1.el10_2, kernel-64k-core-6.12.0-211.63.1.el10_2 +29
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) kernel-tools-libs-devel-6.12.0-211.63.1.el10_2, libperf-6.12.0-211.63.1.el10_2
    • Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal-6.12.0-211.63.1.el10_2
    • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt-6.12.0-211.63.1.el10_2, kernel-rt-64k-6.12.0-211.63.1.el10_2, kernel-rt-64k-core-6.12.0-211.63.1.el10_2 +21
    • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt-6.12.0-211.63.1.el10_2, kernel-rt-core-6.12.0-211.63.1.el10_2, kernel-rt-debug-6.12.0-211.63.1.el10_2 +9
  • RHSA-2026:77218 Released 2026-10-07 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream E4S (v.9.4) kernel-64k-debug-devel-5.14.0-427.154.1.el9_4, kernel-64k-debug-devel-matched-5.14.0-427.154.1.el9_4, kernel-64k-devel-5.14.0-427.154.1.el9_4 +11
    • Red Hat Enterprise Linux BaseOS E4S (v.9.4) bpftool-7.3.0-427.154.1.el9_4, kernel-5.14.0-427.154.1.el9_4, kernel-64k-5.14.0-427.154.1.el9_4 +29
    • Red Hat Enterprise Linux Real Time E4S (v.9.4) kernel-rt-5.14.0-427.154.1.el9_4, kernel-rt-core-5.14.0-427.154.1.el9_4, kernel-rt-debug-5.14.0-427.154.1.el9_4 +9
    • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4) kernel-rt-5.14.0-427.154.1.el9_4, kernel-rt-core-5.14.0-427.154.1.el9_4, kernel-rt-debug-5.14.0-427.154.1.el9_4 +11

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 9AffectedNo fix yet
10Base-SMTVFixed RHSA-2026:76738
Red Hat CodeReady Linux Builder EUS (v.9.6)Fixed RHSA-2026:77219
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:76738
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:76739
Red Hat Enterprise Linux AppStream E4S (v.9.2)Fixed RHSA-2026:92993
Red Hat Enterprise Linux AppStream E4S (v.9.4)Fixed RHSA-2026:77218
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:83707
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:77219
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:76738
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:76739
Red Hat Enterprise Linux BaseOS E4S (v.9.2)Fixed RHSA-2026:92993
Red Hat Enterprise Linux BaseOS E4S (v.9.4)Fixed RHSA-2026:77218
Red Hat Enterprise Linux BaseOS EUS (v. 10.0)Fixed RHSA-2026:83707
Red Hat Enterprise Linux BaseOS EUS (v.9.6)Fixed RHSA-2026:77219
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:76738
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:76739
Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)Fixed RHSA-2026:83707
Red Hat Enterprise Linux Hidden (v. 10)Fixed RHSA-2026:76738
Red Hat Enterprise Linux Real Time (v. 10)Fixed RHSA-2026:76738
Red Hat Enterprise Linux Real Time (v. 9)Fixed RHSA-2026:76739
Red Hat Enterprise Linux Real Time E4S (v.9.2)Fixed RHSA-2026:93047
Red Hat Enterprise Linux Real Time E4S (v.9.4)Fixed RHSA-2026:77218
Red Hat Enterprise Linux Real Time EUS (v. 10.0)Fixed RHSA-2026:83707
Red Hat Enterprise Linux Real Time EUS (v.9.6)Fixed RHSA-2026:77219
Red Hat Enterprise Linux Real Time for NFV (v. 10)Fixed RHSA-2026:76738
Red Hat Enterprise Linux Real Time for NFV (v. 9)Fixed RHSA-2026:76739
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2)Fixed RHSA-2026:93047
Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4)Fixed RHSA-2026:77218
Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0)Fixed RHSA-2026:83707
Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6)Fixed RHSA-2026:77219
Not affected: 2 products
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-63984
  2. 2026-10-03 Alias added: GHSA-6hh9-w4p2-c5qm
  3. 2026-10-07 Fix available: RHSA-2026:77218 · Red Hat
  4. 2026-10-07 Fix available: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4), Red Hat Enterprise Linux Real Time E4S (v.9.4) +1 · Red Hat
  5. 2026-10-09 Fix available: RHSA-2026:77219 · Red Hat
  6. 2026-10-09 Fix available: RHSA-2026:76739 · Red Hat
  7. 2026-10-09 Fix available: Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux AppStream EUS (v.9.6) +7 · Red Hat
  8. 2026-10-16 CISA SSVC decision points changed
  9. 2026-10-18 Fix available: RHSA-2026:83707 · Red Hat
  10. 2026-10-18 Fix available: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux BaseOS EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) +2 · Red Hat
  11. 2026-10-19 Weakness changed · CISA ADP
  12. 2026-10-26 Fix available: RHSA-2026:76738 · Red Hat
  13. 2026-10-26 Fix available: 10Base-SMTV, Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10) +4 · Red Hat
  14. 2026-10-27 CVSS score changed · Red Hat
  15. 2026-10-30 Fix available: RHSA-2026:93047 · Red Hat
  16. 2026-10-30 Fix available: Red Hat Enterprise Linux AppStream E4S (v.9.2), Red Hat Enterprise Linux BaseOS E4S (v.9.2), Red Hat Enterprise Linux Real Time E4S (v.9.2) +1 · Red Hat
  17. 2026-10-31 Fix available: RHSA-2026:92993 · 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