CVE-2023-53821 (GCVE-0-2023-53821)
Vulnerability from cvelistv5 – Published: 2025-12-09 01:29 – Updated: 2025-12-09 01:29
VLAI?
Title
ip6_vti: fix slab-use-after-free in decode_session6
Summary
In the Linux kernel, the following vulnerability has been resolved:
ip6_vti: fix slab-use-after-free in decode_session6
When ipv6_vti device is set to the qdisc of the sfb type, the cb field
of the sent skb may be modified during enqueuing. Then,
slab-use-after-free may occur when ipv6_vti device sends IPv6 packets.
The stack information is as follows:
BUG: KASAN: slab-use-after-free in decode_session6+0x103f/0x1890
Read of size 1 at addr ffff88802e08edc2 by task swapper/0/0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.4.0-next-20230707-00001-g84e2cad7f979 #410
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014
Call Trace:
<IRQ>
dump_stack_lvl+0xd9/0x150
print_address_description.constprop.0+0x2c/0x3c0
kasan_report+0x11d/0x130
decode_session6+0x103f/0x1890
__xfrm_decode_session+0x54/0xb0
vti6_tnl_xmit+0x3e6/0x1ee0
dev_hard_start_xmit+0x187/0x700
sch_direct_xmit+0x1a3/0xc30
__qdisc_run+0x510/0x17a0
__dev_queue_xmit+0x2215/0x3b10
neigh_connected_output+0x3c2/0x550
ip6_finish_output2+0x55a/0x1550
ip6_finish_output+0x6b9/0x1270
ip6_output+0x1f1/0x540
ndisc_send_skb+0xa63/0x1890
ndisc_send_rs+0x132/0x6f0
addrconf_rs_timer+0x3f1/0x870
call_timer_fn+0x1a0/0x580
expire_timers+0x29b/0x4b0
run_timer_softirq+0x326/0x910
__do_softirq+0x1d4/0x905
irq_exit_rcu+0xb7/0x120
sysvec_apic_timer_interrupt+0x97/0xc0
</IRQ>
Allocated by task 9176:
kasan_save_stack+0x22/0x40
kasan_set_track+0x25/0x30
__kasan_slab_alloc+0x7f/0x90
kmem_cache_alloc_node+0x1cd/0x410
kmalloc_reserve+0x165/0x270
__alloc_skb+0x129/0x330
netlink_sendmsg+0x9b1/0xe30
sock_sendmsg+0xde/0x190
____sys_sendmsg+0x739/0x920
___sys_sendmsg+0x110/0x1b0
__sys_sendmsg+0xf7/0x1c0
do_syscall_64+0x39/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Freed by task 9176:
kasan_save_stack+0x22/0x40
kasan_set_track+0x25/0x30
kasan_save_free_info+0x2b/0x40
____kasan_slab_free+0x160/0x1c0
slab_free_freelist_hook+0x11b/0x220
kmem_cache_free+0xf0/0x490
skb_free_head+0x17f/0x1b0
skb_release_data+0x59c/0x850
consume_skb+0xd2/0x170
netlink_unicast+0x54f/0x7f0
netlink_sendmsg+0x926/0xe30
sock_sendmsg+0xde/0x190
____sys_sendmsg+0x739/0x920
___sys_sendmsg+0x110/0x1b0
__sys_sendmsg+0xf7/0x1c0
do_syscall_64+0x39/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
The buggy address belongs to the object at ffff88802e08ed00
which belongs to the cache skbuff_small_head of size 640
The buggy address is located 194 bytes inside of
freed 640-byte region [ffff88802e08ed00, ffff88802e08ef80)
As commit f855691975bb ("xfrm6: Fix the nexthdr offset in
_decode_session6.") showed, xfrm_decode_session was originally intended
only for the receive path. IP6CB(skb)->nhoff is not set during
transmission. Therefore, set the cb field in the skb to 0 before
sending packets.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
| Vendor | Product | Version | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux |
Affected:
f855691975bb06373a98711e4cfe2c224244b536 , < 0f0ab8d52ee0062b28367dea23c29e254a26d7db
(git)
Affected: f855691975bb06373a98711e4cfe2c224244b536 , < fa6c6c04f6c9b21b315023f487e5a07ae7fcf647 (git) Affected: f855691975bb06373a98711e4cfe2c224244b536 , < eb47e612e59c358c3968a92f90dd36c78c9a2106 (git) Affected: f855691975bb06373a98711e4cfe2c224244b536 , < ec23b25e5687dbd644c0f57bcb6af22dd5a6dd36 (git) Affected: f855691975bb06373a98711e4cfe2c224244b536 , < a1639a82ce14af76b6419778d343ccbff86ee626 (git) Affected: f855691975bb06373a98711e4cfe2c224244b536 , < 55ad2309205cc00c585344374c7472420e1b2c12 (git) Affected: f855691975bb06373a98711e4cfe2c224244b536 , < c070688bfbe7759e61e697e421b2a331b0dd74bc (git) Affected: f855691975bb06373a98711e4cfe2c224244b536 , < 9fd41f1ba638938c9a1195d09bc6fa3be2712f25 (git) |
|||||||
|
|||||||||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/ipv6/ip6_vti.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"status": "affected",
"version": "f855691975bb06373a98711e4cfe2c224244b536",
"versionType": "git"
},
{
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"status": "affected",
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"versionType": "git"
},
{
"lessThan": "eb47e612e59c358c3968a92f90dd36c78c9a2106",
"status": "affected",
"version": "f855691975bb06373a98711e4cfe2c224244b536",
"versionType": "git"
},
{
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"versionType": "git"
},
{
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"versionType": "git"
},
{
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"status": "affected",
"version": "f855691975bb06373a98711e4cfe2c224244b536",
"versionType": "git"
},
{
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"versionType": "git"
},
{
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"status": "affected",
"version": "f855691975bb06373a98711e4cfe2c224244b536",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/ipv6/ip6_vti.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "3.19"
},
{
"lessThan": "3.19",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "4.14.*",
"status": "unaffected",
"version": "4.14.324",
"versionType": "semver"
},
{
"lessThanOrEqual": "4.19.*",
"status": "unaffected",
"version": "4.19.293",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.4.*",
"status": "unaffected",
"version": "5.4.255",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.192",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.128",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.47",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.4.*",
"status": "unaffected",
"version": "6.4.12",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.5",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "4.14.324",
"versionStartIncluding": "3.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "4.19.293",
"versionStartIncluding": "3.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.4.255",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.192",
"versionStartIncluding": "3.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.128",
"versionStartIncluding": "3.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.47",
"versionStartIncluding": "3.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.4.12",
"versionStartIncluding": "3.19",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.5",
"versionStartIncluding": "3.19",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nip6_vti: fix slab-use-after-free in decode_session6\n\nWhen ipv6_vti device is set to the qdisc of the sfb type, the cb field\nof the sent skb may be modified during enqueuing. Then,\nslab-use-after-free may occur when ipv6_vti device sends IPv6 packets.\n\nThe stack information is as follows:\nBUG: KASAN: slab-use-after-free in decode_session6+0x103f/0x1890\nRead of size 1 at addr ffff88802e08edc2 by task swapper/0/0\nCPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.4.0-next-20230707-00001-g84e2cad7f979 #410\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014\nCall Trace:\n\u003cIRQ\u003e\ndump_stack_lvl+0xd9/0x150\nprint_address_description.constprop.0+0x2c/0x3c0\nkasan_report+0x11d/0x130\ndecode_session6+0x103f/0x1890\n__xfrm_decode_session+0x54/0xb0\nvti6_tnl_xmit+0x3e6/0x1ee0\ndev_hard_start_xmit+0x187/0x700\nsch_direct_xmit+0x1a3/0xc30\n__qdisc_run+0x510/0x17a0\n__dev_queue_xmit+0x2215/0x3b10\nneigh_connected_output+0x3c2/0x550\nip6_finish_output2+0x55a/0x1550\nip6_finish_output+0x6b9/0x1270\nip6_output+0x1f1/0x540\nndisc_send_skb+0xa63/0x1890\nndisc_send_rs+0x132/0x6f0\naddrconf_rs_timer+0x3f1/0x870\ncall_timer_fn+0x1a0/0x580\nexpire_timers+0x29b/0x4b0\nrun_timer_softirq+0x326/0x910\n__do_softirq+0x1d4/0x905\nirq_exit_rcu+0xb7/0x120\nsysvec_apic_timer_interrupt+0x97/0xc0\n\u003c/IRQ\u003e\nAllocated by task 9176:\nkasan_save_stack+0x22/0x40\nkasan_set_track+0x25/0x30\n__kasan_slab_alloc+0x7f/0x90\nkmem_cache_alloc_node+0x1cd/0x410\nkmalloc_reserve+0x165/0x270\n__alloc_skb+0x129/0x330\nnetlink_sendmsg+0x9b1/0xe30\nsock_sendmsg+0xde/0x190\n____sys_sendmsg+0x739/0x920\n___sys_sendmsg+0x110/0x1b0\n__sys_sendmsg+0xf7/0x1c0\ndo_syscall_64+0x39/0xb0\nentry_SYSCALL_64_after_hwframe+0x63/0xcd\nFreed by task 9176:\nkasan_save_stack+0x22/0x40\nkasan_set_track+0x25/0x30\nkasan_save_free_info+0x2b/0x40\n____kasan_slab_free+0x160/0x1c0\nslab_free_freelist_hook+0x11b/0x220\nkmem_cache_free+0xf0/0x490\nskb_free_head+0x17f/0x1b0\nskb_release_data+0x59c/0x850\nconsume_skb+0xd2/0x170\nnetlink_unicast+0x54f/0x7f0\nnetlink_sendmsg+0x926/0xe30\nsock_sendmsg+0xde/0x190\n____sys_sendmsg+0x739/0x920\n___sys_sendmsg+0x110/0x1b0\n__sys_sendmsg+0xf7/0x1c0\ndo_syscall_64+0x39/0xb0\nentry_SYSCALL_64_after_hwframe+0x63/0xcd\nThe buggy address belongs to the object at ffff88802e08ed00\nwhich belongs to the cache skbuff_small_head of size 640\nThe buggy address is located 194 bytes inside of\nfreed 640-byte region [ffff88802e08ed00, ffff88802e08ef80)\n\nAs commit f855691975bb (\"xfrm6: Fix the nexthdr offset in\n_decode_session6.\") showed, xfrm_decode_session was originally intended\nonly for the receive path. IP6CB(skb)-\u003enhoff is not set during\ntransmission. Therefore, set the cb field in the skb to 0 before\nsending packets."
}
],
"providerMetadata": {
"dateUpdated": "2025-12-09T01:29:34.073Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/0f0ab8d52ee0062b28367dea23c29e254a26d7db"
},
{
"url": "https://git.kernel.org/stable/c/fa6c6c04f6c9b21b315023f487e5a07ae7fcf647"
},
{
"url": "https://git.kernel.org/stable/c/eb47e612e59c358c3968a92f90dd36c78c9a2106"
},
{
"url": "https://git.kernel.org/stable/c/ec23b25e5687dbd644c0f57bcb6af22dd5a6dd36"
},
{
"url": "https://git.kernel.org/stable/c/a1639a82ce14af76b6419778d343ccbff86ee626"
},
{
"url": "https://git.kernel.org/stable/c/55ad2309205cc00c585344374c7472420e1b2c12"
},
{
"url": "https://git.kernel.org/stable/c/c070688bfbe7759e61e697e421b2a331b0dd74bc"
},
{
"url": "https://git.kernel.org/stable/c/9fd41f1ba638938c9a1195d09bc6fa3be2712f25"
}
],
"title": "ip6_vti: fix slab-use-after-free in decode_session6",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2023-53821",
"datePublished": "2025-12-09T01:29:34.073Z",
"dateReserved": "2025-12-09T01:27:17.824Z",
"dateUpdated": "2025-12-09T01:29:34.073Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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