CVE-2026-23277 (GCVE-0-2026-23277)
Vulnerability from cvelistv5
Published
2026-03-20 08:08
Modified
2026-04-18 08:57
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
net/sched: teql: fix NULL pointer dereference in iptunnel_xmit on TEQL slave xmit
teql_master_xmit() calls netdev_start_xmit(skb, slave) to transmit
through slave devices, but does not update skb->dev to the slave device
beforehand.
When a gretap tunnel is a TEQL slave, the transmit path reaches
iptunnel_xmit() which saves dev = skb->dev (still pointing to teql0
master) and later calls iptunnel_xmit_stats(dev, pkt_len). This
function does:
get_cpu_ptr(dev->tstats)
Since teql_master_setup() does not set dev->pcpu_stat_type to
NETDEV_PCPU_STAT_TSTATS, the core network stack never allocates tstats
for teql0, so dev->tstats is NULL. get_cpu_ptr(NULL) computes
NULL + __per_cpu_offset[cpu], resulting in a page fault.
BUG: unable to handle page fault for address: ffff8880e6659018
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 68bc067 P4D 68bc067 PUD 0
Oops: Oops: 0002 [#1] SMP KASAN PTI
RIP: 0010:iptunnel_xmit (./include/net/ip_tunnels.h:664 net/ipv4/ip_tunnel_core.c:89)
Call Trace:
<TASK>
ip_tunnel_xmit (net/ipv4/ip_tunnel.c:847)
__gre_xmit (net/ipv4/ip_gre.c:478)
gre_tap_xmit (net/ipv4/ip_gre.c:779)
teql_master_xmit (net/sched/sch_teql.c:319)
dev_hard_start_xmit (net/core/dev.c:3887)
sch_direct_xmit (net/sched/sch_generic.c:347)
__dev_queue_xmit (net/core/dev.c:4802)
neigh_direct_output (net/core/neighbour.c:1660)
ip_finish_output2 (net/ipv4/ip_output.c:237)
__ip_finish_output.part.0 (net/ipv4/ip_output.c:315)
ip_mc_output (net/ipv4/ip_output.c:369)
ip_send_skb (net/ipv4/ip_output.c:1508)
udp_send_skb (net/ipv4/udp.c:1195)
udp_sendmsg (net/ipv4/udp.c:1485)
inet_sendmsg (net/ipv4/af_inet.c:859)
__sys_sendto (net/socket.c:2206)
Fix this by setting skb->dev = slave before calling
netdev_start_xmit(), so that tunnel xmit functions see the correct
slave device with properly allocated tstats.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 039f50629b7f860f36644ed1f34b27da9aa62f43 Version: 039f50629b7f860f36644ed1f34b27da9aa62f43 Version: 039f50629b7f860f36644ed1f34b27da9aa62f43 Version: 039f50629b7f860f36644ed1f34b27da9aa62f43 Version: 039f50629b7f860f36644ed1f34b27da9aa62f43 Version: 039f50629b7f860f36644ed1f34b27da9aa62f43 Version: 039f50629b7f860f36644ed1f34b27da9aa62f43 Version: 039f50629b7f860f36644ed1f34b27da9aa62f43 |
||
{
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: teql: fix NULL pointer dereference in iptunnel_xmit on TEQL slave xmit\n\nteql_master_xmit() calls netdev_start_xmit(skb, slave) to transmit\nthrough slave devices, but does not update skb-\u003edev to the slave device\nbeforehand.\n\nWhen a gretap tunnel is a TEQL slave, the transmit path reaches\niptunnel_xmit() which saves dev = skb-\u003edev (still pointing to teql0\nmaster) and later calls iptunnel_xmit_stats(dev, pkt_len). This\nfunction does:\n\n get_cpu_ptr(dev-\u003etstats)\n\nSince teql_master_setup() does not set dev-\u003epcpu_stat_type to\nNETDEV_PCPU_STAT_TSTATS, the core network stack never allocates tstats\nfor teql0, so dev-\u003etstats is NULL. get_cpu_ptr(NULL) computes\nNULL + __per_cpu_offset[cpu], resulting in a page fault.\n\n BUG: unable to handle page fault for address: ffff8880e6659018\n #PF: supervisor write access in kernel mode\n #PF: error_code(0x0002) - not-present page\n PGD 68bc067 P4D 68bc067 PUD 0\n Oops: Oops: 0002 [#1] SMP KASAN PTI\n RIP: 0010:iptunnel_xmit (./include/net/ip_tunnels.h:664 net/ipv4/ip_tunnel_core.c:89)\n Call Trace:\n \u003cTASK\u003e\n ip_tunnel_xmit (net/ipv4/ip_tunnel.c:847)\n __gre_xmit (net/ipv4/ip_gre.c:478)\n gre_tap_xmit (net/ipv4/ip_gre.c:779)\n teql_master_xmit (net/sched/sch_teql.c:319)\n dev_hard_start_xmit (net/core/dev.c:3887)\n sch_direct_xmit (net/sched/sch_generic.c:347)\n __dev_queue_xmit (net/core/dev.c:4802)\n neigh_direct_output (net/core/neighbour.c:1660)\n ip_finish_output2 (net/ipv4/ip_output.c:237)\n __ip_finish_output.part.0 (net/ipv4/ip_output.c:315)\n ip_mc_output (net/ipv4/ip_output.c:369)\n ip_send_skb (net/ipv4/ip_output.c:1508)\n udp_send_skb (net/ipv4/udp.c:1195)\n udp_sendmsg (net/ipv4/udp.c:1485)\n inet_sendmsg (net/ipv4/af_inet.c:859)\n __sys_sendto (net/socket.c:2206)\n\nFix this by setting skb-\u003edev = slave before calling\nnetdev_start_xmit(), so that tunnel xmit functions see the correct\nslave device with properly allocated tstats."
}
],
"providerMetadata": {
"dateUpdated": "2026-04-18T08:57:33.874Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/383493b9940e3d1b5517424081b3e072e20ec43c"
},
{
"url": "https://git.kernel.org/stable/c/6b1f563d670162e188a0f2aec39c24b67b106e17"
},
{
"url": "https://git.kernel.org/stable/c/57c153249143333bbf4ecf927bdf8aa2696ee397"
},
{
"url": "https://git.kernel.org/stable/c/59b06d8b9bdb6b64b3c534c18da68bce5ccd31be"
},
{
"url": "https://git.kernel.org/stable/c/81a43e8005366f16e629d8c95dfe05beaa8d36a7"
},
{
"url": "https://git.kernel.org/stable/c/0bad9c86edd22dec4df83c2b29872d66fd8a2ff4"
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{
"url": "https://git.kernel.org/stable/c/21ea283c2750c8307aa35ee832b0951cc993c27d"
},
{
"url": "https://git.kernel.org/stable/c/0cc0c2e661af418bbf7074179ea5cfffc0a5c466"
}
],
"title": "net/sched: teql: fix NULL pointer dereference in iptunnel_xmit on TEQL slave xmit",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-23277",
"datePublished": "2026-03-20T08:08:57.394Z",
"dateReserved": "2026-01-13T15:37:45.991Z",
"dateUpdated": "2026-04-18T08:57:33.874Z",
"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 seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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