ipv6: mcast: use copy-on-write RCU updates in ip6_mc_source()
In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: use copy-on-write RCU updates in ip6_mc_source() pmc->sflist is read locklessly under rcu_read_lock() by inet6_mc_check() during packet reception in the UDP and RAW multicast receive paths. ip6_mc_source() mutated psl->sl_addr and psl->sl_count in-place when adding or removing a source filter. Additionally, when expanding the filter buffer, newpsl was published via rcu_assign_pointer() before writing the new source into the array. Because 16-byte struct in6_addr writes are not atomic and array shifting is not synchronized with RCU readers, concurrent readers in inet6_mc_check() could read torn IPv6 addresses or observe duplicated/missed source entries. Fix this by switching ip6_mc_source() to copy-on-write RCU updates: allocate and fully populate newpsl before publishing it via rcu_assign_pointer(), and reclaim the old filter via kfree_rcu(), matching ip6_mc_msfilter(). Also remove the now unused IP6_SFBLOCK macro.
CVE-2026-98101
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-2026-98101
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": "882ba1f73c06831f2a21044ebd8864c485ac04f2",
"lessThan": "ac51321d3b2391860a935820ebcf4d8b9bb16a8a",
"versionType": "git"
},
{
"status": "affected",
"version": "882ba1f73c06831f2a21044ebd8864c485ac04f2",
"lessThan": "dba00514bf668c26cb4900e9f0da84bf96bf065a",
"versionType": "git"
},
{
"status": "affected",
"version": "882ba1f73c06831f2a21044ebd8864c485ac04f2",
"lessThan": "2c2091e2ee93049fc513ad1e6c99d8b6c809f467",
"versionType": "git"
},
{
"status": "affected",
"version": "882ba1f73c06831f2a21044ebd8864c485ac04f2",
"lessThan": "20db91a052332ef5552bd2f651ffb9db911cf67b",
"versionType": "git"
},
{
"status": "affected",
"version": "882ba1f73c06831f2a21044ebd8864c485ac04f2",
"lessThan": "c073d1b070f171d206b19c98d71739a97f15b3f1",
"versionType": "git"
},
{
"status": "affected",
"version": "47c75e3923c8d562fea8daf0ccf31546a7bef0ea",
"versionType": "git"
},
{
"status": "affected",
"version": "5.10.261",
"lessThan": "5.11",
"versionType": "semver"
}
],
"programFiles": [
"include/net/if_inet6.h",
"net/ipv6/mcast.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.13"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.13",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.158",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.112",
"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": [
"include/net/if_inet6.h",
"net/ipv6/mcast.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98101
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #38203 · Revision 1
- Added to Heist Feed
- Publisher date