flow_dissector: avoid u16 truncation of hlen in bpf_flow_dissect()
In the Linux kernel, the following vulnerability has been resolved: flow_dissector: avoid u16 truncation of hlen in bpf_flow_dissect() bpf_flow_dissect() sanitizes the offsets returned by the BPF program with clamp_t(u16, ..., hlen). If hlen is bigger than 65535, the upper bound is truncated before the comparison. For instance, with hlen == 65536, both nhoff and thoff are forced to zero, even if the program returned sane values. This is the same class of bug as the one fixed in commit 99bda1ecbd56 ("flow_dissector: avoid u16 truncation of skb->len when computing thoff"). That fix does not cover the BPF path, because __skb_flow_dissect() returns early when a BPF flow dissector handles the packet. struct bpf_flow_keys stores nhoff and thoff as u16, so cap hlen to U16_MAX before clamping. Found by sashiko while reviewing the commit above.
CVE-2026-98950
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-2026-98950
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": "d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9",
"lessThan": "c44c02c930c6583b235a1937c69ff716c4bb4514",
"versionType": "git"
},
{
"status": "affected",
"version": "d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9",
"lessThan": "3fb5ad2951a6df92c98f4f06cd70f20c50a2eb2a",
"versionType": "git"
},
{
"status": "affected",
"version": "d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9",
"lessThan": "cc18eb0e9941162c03f03f411ed7f6c339d91fa0",
"versionType": "git"
},
{
"status": "affected",
"version": "d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9",
"lessThan": "61b43a51a55929ec040bee3ea51af2121b956d05",
"versionType": "git"
},
{
"status": "affected",
"version": "d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9",
"lessThan": "f202578efc738b883cfa04889eb97328914265a7",
"versionType": "git"
}
],
"programFiles": [
"net/core/flow_dissector.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.20"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.20",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.113",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.57",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.11",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/core/flow_dissector.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98950
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #52808 · Revision 1
- Added to Heist Feed
- Publisher date