net: ipv6: keep room for the mac header in dst_dev_overhead()
In the Linux kernel, the following vulnerability has been resolved: net: ipv6: keep room for the mac header in dst_dev_overhead() The seg6, ioam6 and rpl lwtunnels size their skb_cow_head() request as the length they are about to push plus dst_dev_overhead(), then push the new headers and rebuild the mac header below them with skb_mac_header_rebuild(). That rebuild needs skb->mac_len of headroom, but dst_dev_overhead() leaves LL_RESERVED_SPACE() of the egress device, 16 bytes for plain Ethernet. Where the mac header is longer than that, as it is on ingress through a VLAN device with reorder_hdr off, the rebuild runs out of room: skb_set_mac_header(skb, -skb->mac_len) computes a negative offset, stores it unchecked in the u16 skb->mac_header, and the memmove that follows writes skb->mac_len bytes about 64 KB past skb->head. Forwarding plain ping6 traffic through such a device reproduces it on all five seg6 encapsulation modes and on the rpl and ioam6 inline paths; skb->mac_header comes back as 65534 on a 704-byte head. Return the larger of the two. The helper already returns skb->mac_len when it has no dst, so this only makes the other branch agree, and it covers every caller rather than each call site in turn.
CVE-2026-98570
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-2026-98570
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": "dce525185bc92864e5a318040285ee070563fe34",
"lessThan": "36c07127924f11fc5741a780abcaaf808fe9ef13",
"versionType": "git"
},
{
"status": "affected",
"version": "dce525185bc92864e5a318040285ee070563fe34",
"lessThan": "87cd6b717e4069dca34e0866e57eaeb44d3b173e",
"versionType": "git"
},
{
"status": "affected",
"version": "8471e228448a818e4c27cab4b681b2e758e46cf5",
"versionType": "git"
},
{
"status": "affected",
"version": "c432cd18a07b623651ed15ea167bd303467004cc",
"versionType": "git"
},
{
"status": "affected",
"version": "634710a372ba65bee667c2f6e58a97658c639eab",
"versionType": "git"
},
{
"status": "affected",
"version": "c447c5a9c47bb4858ab12bf90879fe595d2b7f46",
"versionType": "git"
},
{
"status": "affected",
"version": "ab9de9c48316d2622d3bf353916b99971570e2c9",
"versionType": "git"
},
{
"status": "affected",
"version": "2fcc9f3798ef82399564d247458e69abd10e683b",
"versionType": "git"
},
{
"status": "affected",
"version": "371d8dc298b4f59e99b4564ac5d906fce0932c69",
"versionType": "git"
},
{
"status": "affected",
"version": "b26f015dfb07b6be12d005a0ed0c5c43b7bedbf3",
"versionType": "git"
},
{
"status": "affected",
"version": "c0b11dc50590e10590b39dcda79835cd32f49d00",
"versionType": "git"
},
{
"status": "affected",
"version": "4c12c3c8abd8b888945d31e7bdbb0d8b73032fc5",
"versionType": "git"
},
{
"status": "affected",
"version": "25d8e065c7972dc98fd7a4cac322d5367eaede88",
"versionType": "git"
},
{
"status": "affected",
"version": "4a855c5aec41bf84922224ab7a74e088776e3ac4",
"versionType": "git"
},
{
"status": "affected",
"version": "a9f0407414e16176fdbbbd298c9e18d6dfdf96bc",
"versionType": "git"
},
{
"status": "affected",
"version": "6.12.16",
"lessThan": "6.13",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.13.4",
"lessThan": "6.14",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.15.179",
"lessThan": "5.16",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.1.130",
"lessThan": "6.2",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.6.81",
"lessThan": "6.7",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.10.235",
"lessThan": "5.11",
"versionType": "semver"
}
],
"programFiles": [
"include/net/dst.h"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.14"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.14",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "7.2.9",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"include/net/dst.h"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98570
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #38590 · Revision 1
- Added to Heist Feed
- Publisher date