slip: reject VJ receive packets on instances with no rstate array
In the Linux kernel, the following vulnerability has been resolved: slip: reject VJ receive packets on instances with no rstate array slhc_init() accepts rslots == 0 as a valid configuration, with the documented meaning of 'no receive compression'. In that case the allocation loop in slhc_init() is skipped, so comp->rstate stays NULL and comp->rslot_limit stays 0 (from the kzalloc of struct slcompress). The receive helpers do not defend against that configuration. slhc_uncompress() dereferences comp->rstate[x] when the VJ header carries an explicit connection ID, and slhc_remember() later assigns cs = &comp->rstate[...] after only comparing the packet's slot number to comp->rslot_limit. Because rslot_limit is 0, slot 0 passes the range check, and the code dereferences a NULL rstate. The configuration is reachable in-tree through PPP. PPPIOCSMAXCID stores its argument in a signed int, and (val >> 16) uses arithmetic shift. Passing 0xffff0000 therefore sign-extends to -1, so val2 + 1 is 0 and ppp_generic.c ends up calling slhc_init(0, 1). Because /dev/ppp open is gated by ns_capable(CAP_NET_ADMIN), the whole path is reachable from an unprivileged user namespace. Once the malformed VJ state is installed, any inbound VJ-compressed or VJ-uncompressed frame that selects slot 0 crashes the kernel in softirq context: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x000
CVE-2026-45842
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-2026-45842
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": "4ab42d78e37a294ac7bc56901d563c642e03c4ae",
"lessThan": "3d71c961febddd855d3ae9a519eeb96c8023f430",
"versionType": "git"
},
{
"status": "affected",
"version": "4ab42d78e37a294ac7bc56901d563c642e03c4ae",
"lessThan": "72304fec672e8aac9ee7b9c475db96b37cca8d8d",
"versionType": "git"
},
{
"status": "affected",
"version": "4ab42d78e37a294ac7bc56901d563c642e03c4ae",
"lessThan": "4aa9eca6fda2919027dfd7a7cc69334982d89586",
"versionType": "git"
},
{
"status": "affected",
"version": "4ab42d78e37a294ac7bc56901d563c642e03c4ae",
"lessThan": "c6980e8b1a86288167f34966fa5219031999b6f1",
"versionType": "git"
},
{
"status": "affected",
"version": "4ab42d78e37a294ac7bc56901d563c642e03c4ae",
"lessThan": "de42f86e2cf5028a97e74c25869d1a962b13c301",
"versionType": "git"
},
{
"status": "affected",
"version": "4ab42d78e37a294ac7bc56901d563c642e03c4ae",
"lessThan": "9e1ff0eead073c4f46d874ad2526b7dda5465faf",
"versionType": "git"
},
{
"status": "affected",
"version": "4ab42d78e37a294ac7bc56901d563c642e03c4ae",
"lessThan": "7b0d9e878ec2b21d99ae8051b3dda59cdb66c152",
"versionType": "git"
},
{
"status": "affected",
"version": "4ab42d78e37a294ac7bc56901d563c642e03c4ae",
"lessThan": "e76607442d5b73e1ba6768f501ef815bb58c2c0e",
"versionType": "git"
},
{
"status": "affected",
"version": "42fc512469e78939c1e419d3310c47de55bdcbb8",
"versionType": "git"
},
{
"status": "affected",
"version": "df085f1cb3acd3d75408ff94f366983873bce7d2",
"versionType": "git"
},
{
"status": "affected",
"version": "a1c3860d3c5fc62bd35f089bcb03f18a37242de9",
"versionType": "git"
},
{
"status": "affected",
"version": "f82699de104eaf8a7ffc2849a566a94818dd8a3c",
"versionType": "git"
},
{
"status": "affected",
"version": "354b254af5c1350de9586af75fe5a821b35bfb33",
"versionType": "git"
},
{
"status": "affected",
"version": "5148857f5d4c812cc918cf4627f7880521e987eb",
"versionType": "git"
},
{
"status": "affected",
"version": "82185755d90c8047c6f4b589c39998ff3d4ca3ad",
"versionType": "git"
},
{
"status": "affected",
"version": "a50a93cc99286dc444c7e5ccc7dfb9d58c2d346d",
"versionType": "git"
},
{
"status": "affected",
"version": "6b4fa561e26526c62636414d267342c945084f44",
"versionType": "git"
},
{
"status": "affected",
"version": "2.6.32.70",
"lessThan": "2.6.33",
"versionType": "semver"
},
{
"status": "affected",
"version": "3.2.75",
"lessThan": "3.3",
"versionType": "semver"
},
{
"status": "affected",
"version": "3.4.111",
"lessThan": "3.5",
"versionType": "semver"
},
{
"status": "affected",
"version": "3.10.96",
"lessThan": "3.11",
"versionType": "semver"
},
{
"status": "affected",
"version": "3.12.53",
"lessThan": "3.13",
"versionType": "semver"
},
{
"status": "affected",
"version": "3.14.60",
"lessThan": "3.15",
"versionType": "semver"
},
{
"status": "affected",
"version": "3.18.27",
"lessThan": "3.19",
"versionType": "semver"
},
{
"status": "affected",
"version": "4.1.17",
"lessThan": "4.2",
"versionType": "semver"
},
{
"status": "affected",
"version": "4.3.5",
"lessThan": "4.4",
"versionType": "semver"
}
],
"programFiles": [
"drivers/net/slip/slhc.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.4"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.4",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.258",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.209",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.175",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.141",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.91",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.33",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.0.10",
"versionType": "semver",
"lessThanOrEqual": "7.0.*"
},
{
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/net/slip/slhc.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-45842
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #28366 · Revision 1
- Added to Heist Feed
- Publisher date