Description

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

ip6_tunnel: fix NEXTHDR_FRAGMENT handling in ip6_tnl_parse_tlv_enc_lim()

syzbot pointed out [1] that NEXTHDR_FRAGMENT handling is broken.

Reading frag_off can only be done if we pulled enough bytes
to skb->head. Currently we might access garbage.

[1]
BUG: KMSAN: uninit-value in ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0
ip6_tnl_parse_tlv_enc_lim+0x94f/0xbb0
ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1326 [inline]
ip6_tnl_start_xmit+0xab2/0x1a70 net/ipv6/ip6_tunnel.c:1432
__netdev_start_xmit include/linux/netdevice.h:4940 [inline]
netdev_start_xmit include/linux/netdevice.h:4954 [inline]
xmit_one net/core/dev.c:3548 [inline]
dev_hard_start_xmit+0x247/0xa10 net/core/dev.c:3564
__dev_queue_xmit+0x33b8/0x5130 net/core/dev.c:4349
dev_queue_xmit include/linux/netdevice.h:3134 [inline]
neigh_connected_output+0x569/0x660 net/core/neighbour.c:1592
neigh_output include/net/neighbour.h:542 [inline]
ip6_finish_output2+0x23a9/0x2b30 net/ipv6/ip6_output.c:137
ip6_finish_output+0x855/0x12b0 net/ipv6/ip6_output.c:222
NF_HOOK_COND include/linux/netfilter.h:303 [inline]
ip6_output+0x323/0x610 net/ipv6/ip6_output.c:243
dst_output include/net/dst.h:451 [inline]
ip6_local_out+0xe9/0x140 net/ipv6/output_core.c:155
ip6_send_skb net/ipv6/ip6_output.c:1952 [inline]
ip6_push_pending_frames+0x1f9/0x560 net/ipv6/ip6_output.c:1972
rawv6_push_pending_frames+0xbe8/0xdf0 net/ipv6/raw.c:582
rawv6_sendmsg+0x2b66/0x2e70 net/ipv6/raw.c:920
inet_se...

Classification

CVE ID: CVE-2024-26633

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 15.26% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/135414f300c5db995e2a2f3bf0f455de9d014aee
https://git.kernel.org/stable/c/3f15ba3dc14e6ee002ea01b4faddc3d49200377c
https://git.kernel.org/stable/c/da23bd709b46168f7dfc36055801011222b076cd
https://git.kernel.org/stable/c/4329426cf6b8e22b798db2331c7ef1dd2a9c748d
https://git.kernel.org/stable/c/62a1fedeb14c7ac0947ef33fadbabd35ed2400a2
https://git.kernel.org/stable/c/687c5d52fe53e602e76826dbd4d7af412747e183
https://git.kernel.org/stable/c/ba8d904c274268b18ef3dc11d3ca7b24a96cb087
https://git.kernel.org/stable/c/d375b98e0248980681e5e56b712026174d617198

Timeline