ppp_async: drop the errored frame instead of resetting its headroom
In the Linux kernel, the following vulnerability has been resolved: ppp_async: drop the errored frame instead of resetting its headroom ppp_receive_nonmp_frame() prepends a two-byte direction tag before running the pass/active BPF filters: *(__be16 *)skb_push(skb, 2) = htons(PPP_FILTER_INBOUND_TAG); Nothing on the receive path guarantees those two bytes of headroom. The frame-error path in ppp_async's process_input_packet() resets a reused skb's headroom to zero while claiming to restore it to a freshly allocated state - but a fresh skb from dev_alloc_skb() carries NET_SKB_PAD: err: if (skb) { /* make skb appear as freshly allocated */ skb_trim(skb, 0); skb_reserve(skb, - skb_headroom(skb)); } ap->rpkt still points at that skb, so the next frame is reassembled into it with no headroom at all. A peer that sends a bad-FCS frame followed by one beginning ff 03 then leaves a single byte of headroom by the time the filter tag is pushed, which lands one byte below skb->head: skbuff: skb_under_panic: len:49 put:2 head:ffff888003c10000 data:ffff888003c0ffff tail:0x30 end:0x640 dev: kernel BUG at net/core/skbuff.c:214! RIP: 0010:skb_panic+0x13e/0x230 Call Trace: skb_push+0xbd/0x100 ppp_receive_nonmp_frame+0x48a/0x1d10 ppp_input+0x4e9/0x2f80 ppp_async_process+0x2a/0xe0 tasklet_action_common+0x20f/0x8a0 handle_softirqs+0x18e/0x590 Kernel panic - not syncing: Fatal exception in interrupt Zeroing the headroom violates the NET_SKB_PAD guarantee that dev_alloc_skb() gives the rest of the re
CVE-2026-98158
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-98158
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6722e78c90054101e6797d5944cdc81af9897a0a",
"lessThan": "25f354c55b8435d1f51b8a0a05a3cfe429358523",
"versionType": "git"
},
{
"status": "affected",
"version": "6722e78c90054101e6797d5944cdc81af9897a0a",
"lessThan": "a86a17745c3e1c6fadd4d6e90c03552dfe531c8c",
"versionType": "git"
},
{
"status": "affected",
"version": "6722e78c90054101e6797d5944cdc81af9897a0a",
"lessThan": "ff035780adb0f49dc2c7ada26b4697849a68bec8",
"versionType": "git"
},
{
"status": "affected",
"version": "6722e78c90054101e6797d5944cdc81af9897a0a",
"lessThan": "c4bb894362d224b699e2f95c6c26707d9654e4a3",
"versionType": "git"
},
{
"status": "affected",
"version": "6722e78c90054101e6797d5944cdc81af9897a0a",
"lessThan": "d0fc3dabfe67caf084e7119ceb2ee23f5ad2f2da",
"versionType": "git"
},
{
"status": "affected",
"version": "6722e78c90054101e6797d5944cdc81af9897a0a",
"lessThan": "0c53eb14975f029abd6b26896a460f0d2aaefe6b",
"versionType": "git"
},
{
"status": "affected",
"version": "6722e78c90054101e6797d5944cdc81af9897a0a",
"lessThan": "717137221c7d90e7c98bda9a370c9da6cbf015e5",
"versionType": "git"
},
{
"status": "affected",
"version": "6722e78c90054101e6797d5944cdc81af9897a0a",
"lessThan": "8dc5d98a16fa23c00999aecf10018c9f69fa5bf4",
"versionType": "git"
}
],
"programFiles": [
"drivers/net/ppp/ppp_async.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.15"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "2.6.15",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.271",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.222",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.189",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.158",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.111",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.53",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.7",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/net/ppp/ppp_async.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98158
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #38248 · Revision 1
- Added to Heist Feed
- Publisher date