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CVE-2026-98532

Linux: ipv6: do not let ipv6_find_hdr() return an offset past the packet end

Linux LinuxOperating systems
Open in ThreatlineRecord JSON
CVSS
NoneNot scored
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.22%Chance of exploitation activity in the next 30 days, higher than 11% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in531255de8971c06d5d5986f85fdc2525d707ba71Also 543354c6efb27eae3372a3a9674aeaa2a86e2b2c, 1c70275ca87e769e1a52abc644d61372d8c016cb and 2 moreCVE List
Published18 Oct 2026Updated 19 Oct 2026CVE List

What fixes it

  • 531255de8971c06d5d5986f85fdc2525d707ba71LinuxCVE List
  • 543354c6efb27eae3372a3a9674aeaa2a86e2b2cLinuxCVE List
  • 1c70275ca87e769e1a52abc644d61372d8c016cbLinuxCVE List
  • 1d42828565889632068fbc2983c34d57c66af4e0LinuxCVE List
  • 4254d5878c320c19961dd0b8e1d0aca4800d8b7dLinuxCVE List

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

In the Linux kernel, the following vulnerability has been resolved:

ipv6: do not let ipv6_find_hdr() return an offset past the packet end

ipv6_find_hdr() walks the extension header chain, skipping each header by the length that header itself declares. ipv6_optlen() returns up to 2048, and the skip is never checked against skb->len, so the offset stored in *offset can point past the end of the packet.

openvswitch installs that offset as the transport header, and update_ipv6_checksum() then reads and writes the transport checksum field out of bounds:

BUG: KASAN: slab-use-after-free in inet_proto_csum_replace16+0x445/0x470 Read of size 2 at addr ffff88810b754b06 by task ovs_ipv6_oob/629 CPU: 4 UID: 1000 PID: 629 Comm: ovs_ipv6_oob Tainted: G N 7.3.0-rc3+ #348 Call Trace: inet_proto_csum_replace16+0x445/0x470 set_ipv6_addr+0x3dd/0x460 do_execute_actions+0x6a3d/0x7c40 ovs_execute_actions+0xfd/0x480 ovs_packet_cmd_execute+0xc38/0xf20 genl_rcv_msg+0x59e/0x870 netlink_rcv_skb+0x18b/0x450 genl_rcv+0x2d/0x40 netlink_unicast+0x6bc/0xa20

The buggy address belongs to the object at ffff88810b754980 which belongs to the cache skbuff_small_head of size 704 The buggy address is located 390 bytes inside of freed 704-byte region [ffff88810b754980, ffff88810b754c40)

Other callers use that offset too, so bound it here rather than in one caller.

Reject a header whose declared length does not fit in the packet. ipv6_find_hdr() already fails with -EBADMSG on a malformed chain, so this adds no new failure mode.

Text from CVE List

Affected versions 18

  • Linuxaffected: f8f626754ebeca613cf1af2e6f890cfde0e74d5b before ca96b38730e31357ef4a9d76af1336958ac670d7CVE List
  • Linuxaffected: f8f626754ebeca613cf1af2e6f890cfde0e74d5b before 531255de8971c06d5d5986f85fdc2525d707ba71CVE List
  • Linuxaffected: f8f626754ebeca613cf1af2e6f890cfde0e74d5b before 543354c6efb27eae3372a3a9674aeaa2a86e2b2cCVE List
  • Linuxaffected: f8f626754ebeca613cf1af2e6f890cfde0e74d5b before dc92cb972e86790b8078337ec41015b748b8f8e5CVE List
  • Linuxaffected: f8f626754ebeca613cf1af2e6f890cfde0e74d5b before 1c70275ca87e769e1a52abc644d61372d8c016cbCVE List
  • Linuxaffected: f8f626754ebeca613cf1af2e6f890cfde0e74d5b before 1d42828565889632068fbc2983c34d57c66af4e0CVE List
  • Linuxaffected: f8f626754ebeca613cf1af2e6f890cfde0e74d5b before 4254d5878c320c19961dd0b8e1d0aca4800d8b7dCVE List
  • Linuxaffected: f8f626754ebeca613cf1af2e6f890cfde0e74d5b before ee319bd3a0e976af5087cbe59ebc50a66f31d202CVE List
  • Linuxaffected: 3.8CVE List
  • Linuxunaffected: all versions before 3.8CVE List
  • Linuxunaffected: 5.10.271 through 5.10.*CVE List
  • Linuxunaffected: 5.15.222 through 5.15.*CVE List
  • Linuxunaffected: 6.1.189 through 6.1.*CVE List
  • Linuxunaffected: 6.6.158 through 6.6.*CVE List
  • Linuxunaffected: 6.12.112 through 6.12.*CVE List
  • Linuxunaffected: 6.18.55 through 6.18.*CVE List
  • Linuxunaffected: 7.2.9 through 7.2.*CVE List
  • Linuxunaffected: 7.3CVE List

References 8