CVE-2026-23316
published 2026-03-25CVE-2026-23316: In the Linux kernel, the following vulnerability has been resolved: net: ipv4: fix ARM64 alignment fault in multipath hash seed `struct…
PriorityP421medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.12%
2.3th percentile
In the Linux kernel, the following vulnerability has been resolved:
net: ipv4: fix ARM64 alignment fault in multipath hash seed
`struct sysctl_fib_multipath_hash_seed` contains two u32 fields
(user_seed and mp_seed), making it an 8-byte structure with a 4-byte
alignment requirement.
In `fib_multipath_hash_from_keys()`, the code evaluates the entire
struct atomically via `READ_ONCE()`:
mp_seed = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_seed).mp_seed;
While this silently works on GCC by falling back to unaligned regular
loads which the ARM64 kernel tolerates, it causes a fatal kernel panic
when compiled with Clang and LTO enabled.
Commit e35123d83ee3 ("arm64: lto: Strengthen READ_ONCE() to acquire
when CONFIG_LTO=y") strengthens `READ_ONCE()` to use Load-Acquire
instructions (`ldar` / `ldapr`) to prevent compiler reordering bugs
under Clang LTO. Since the macro evaluates the full 8-byte struct,
Clang emits a 64-bit `ldar` instruction. ARM64 architecture strictly
requires `ldar` to be naturally aligned, thus executing it on a 4-byte
aligned address triggers a strict Alignment Fault (FSC = 0x21).
Fix the read side by moving the `READ_ONCE()` directly to the `u32`
member, which emits a safe 32-bit `ldar Wn`.
Furthermore, Eric Dumazet pointed out that `WRITE_ONCE()` on the entire
struct in `proc_fib_multipath_hash_set_seed()` is also flawed. Analysis
shows that Clang splits this 8-byte write into two separate 32-bit
`str` instructions. While this avoids an alignment fault, it destroys
atomicity and exposes a tear-write vulnerability. Fix this by
explicitly splitting the write into two 32-bit `WRITE_ONCE()`
operations.
Finally, add the missing `READ_ONCE()` when reading `user_seed` in
`proc_fib_multipath_hash_seed()` to ensure proper pairing and
concurrency safety.
Affected
15 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | linux | < linux 6.19.8-1 (forky) | linux 6.19.8-1 (forky) |
| linux | linux | — | — |
| linux | linux | >= 4ee2a8cace3fb9a34aea6a56426f89d26dd514f3 < 4bdc94d45d5459f0149085dfc1efe733c8e14f11 | 4bdc94d45d5459f0149085dfc1efe733c8e14f11 |
| linux | linux | >= 4ee2a8cace3fb9a34aea6a56426f89d26dd514f3 < 7e4ad34a8889a6a9e0f6cc7c55d02161fe31a199 | 7e4ad34a8889a6a9e0f6cc7c55d02161fe31a199 |
| linux | linux | >= 4ee2a8cace3fb9a34aea6a56426f89d26dd514f3 < 607e923a3c1b2120de430b3dcde25ed8ad213c0a | 607e923a3c1b2120de430b3dcde25ed8ad213c0a |
| linux | linux | >= 4ee2a8cace3fb9a34aea6a56426f89d26dd514f3 < 4ee7fa6cf78ff26d783d39e2949d14c4c1cd5e7f | 4ee7fa6cf78ff26d783d39e2949d14c4c1cd5e7f |
| linux | linux_kernel | — | — |
| linux | linux_kernel | — | — |
| linux | linux_kernel | >= 0 < 6.19.8-1 | 6.19.8-1 |
| linux | linux_kernel | >= 6.11.0 < 6.12.77 | 6.12.77 |
| linux | linux_kernel | >= 6.11.1 < 6.12.77 | 6.12.77 |
| linux | linux_kernel | >= 6.13 < 6.18.17 | 6.18.17 |
| linux | linux_kernel | >= 6.13.0 < 6.18.17 | 6.18.17 |
| linux | linux_kernel | >= 6.19 < 6.19.7 | 6.19.7 |
| linux | linux_kernel | >= 6.19.0 < 6.19.7 | 6.19.7 |
CVSS provenance
nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
vendor_redhat5.5MEDIUM
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VulDB
Linux Kernel up to 6.12.76/6.18.16/6.19.6/7.0-rc2 net fib_multipath_hash_from_keys denial of service (Nessus ID 303730 / WID-SEC-2026-0861)
vuldb·2026-06-16·CVSS 5.5
CVE-2026-23316 [MEDIUM] Linux Kernel up to 6.12.76/6.18.16/6.19.6/7.0-rc2 net fib_multipath_hash_from_keys denial of service (Nessus ID 303730 / WID-SEC-2026-0861)
A vulnerability has been found in Linux Kernel up to 6.12.76/6.18.16/6.19.6/7.0-rc2 and classified as critical. Affected by this issue is the function fib_multipath_hash_from_keys of the component net. Performing a manipulation results in denial of service.
This vulnerability was named CVE-2026-23316. The attack needs to be approached within the local network. There is no available exploit.
The affected component should be upgraded.
GHSA
GHSA-vcmv-6vcp-286q: In the Linux kernel, the following vulnerability has been resolved:
net: ipv4: fix ARM64 alignment fault in multipath hash seed
`struct sysctl_fib_m
ghsa_unreviewed·2026-03-25
CVE-2026-23316 GHSA-vcmv-6vcp-286q: In the Linux kernel, the following vulnerability has been resolved:
net: ipv4: fix ARM64 alignment fault in multipath hash seed
`struct sysctl_fib_m
In the Linux kernel, the following vulnerability has been resolved:
net: ipv4: fix ARM64 alignment fault in multipath hash seed
`struct sysctl_fib_multipath_hash_seed` contains two u32 fields
(user_seed and mp_seed), making it an 8-byte structure with a 4-byte
alignment requirement.
In `fib_multipath_hash_from_keys()`, the code evaluates the entire
struct atomically via `READ_ONCE()`:
mp_seed = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_seed).mp_seed;
While this silently works on GCC by falling back to unaligned regular
loads which the ARM64 kernel tolerates, it causes a fatal kernel panic
when compiled with Clang and LTO enabled.
Commit e35123d83ee3 ("arm64: lto: Strengthen READ_ONCE() to acquire
when CONFIG_LTO=y") strengthens `READ_ONCE()` to use Load-Acquire
instructions (`lda
OSV
CVE-2026-23316: In the Linux kernel, the following vulnerability has been resolved: net: ipv4: fix ARM64 alignment fault in multipath hash seed `struct sysctl_fib_mul
osv·2026-03-25
CVE-2026-23316 CVE-2026-23316: In the Linux kernel, the following vulnerability has been resolved: net: ipv4: fix ARM64 alignment fault in multipath hash seed `struct sysctl_fib_mul
In the Linux kernel, the following vulnerability has been resolved: net: ipv4: fix ARM64 alignment fault in multipath hash seed `struct sysctl_fib_multipath_hash_seed` contains two u32 fields (user_seed and mp_seed), making it an 8-byte structure with a 4-byte alignment requirement. In `fib_multipath_hash_from_keys()`, the code evaluates the entire struct atomically via `READ_ONCE()`: mp_seed = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_seed).mp_seed; While this silently works on GCC by falling back to unaligned regular loads which the ARM64 kernel tolerates, it causes a fatal kernel panic when compiled with Clang and LTO enabled. Commit e35123d83ee3 ("arm64: lto: Strengthen READ_ONCE() to acquire when CONFIG_LTO=y") strengthens `READ_ONCE()` to use Load-Acquire instructions (`ldar` / `
OSV
net: ipv4: fix ARM64 alignment fault in multipath hash seed
osv·2026-03-25
CVE-2026-23316 net: ipv4: fix ARM64 alignment fault in multipath hash seed
net: ipv4: fix ARM64 alignment fault in multipath hash seed
In the Linux kernel, the following vulnerability has been resolved:
net: ipv4: fix ARM64 alignment fault in multipath hash seed
`struct sysctl_fib_multipath_hash_seed` contains two u32 fields
(user_seed and mp_seed), making it an 8-byte structure with a 4-byte
alignment requirement.
In `fib_multipath_hash_from_keys()`, the code evaluates the entire
struct atomically via `READ_ONCE()`:
mp_seed = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_seed).mp_seed;
While this silently works on GCC by falling back to unaligned regular
loads which the ARM64 kernel tolerates, it causes a fatal kernel panic
when compiled with Clang and LTO enabled.
Commit e35123d83ee3 ("arm64: lto: Strengthen READ_ONCE() to acquire
when CONFIG_LTO=y") str
Red Hat
kernel: net: ipv4: fix ARM64 alignment fault in multipath hash seed
vendor_redhat·2026-03-25·CVSS 5.5
CVE-2026-23316 [MEDIUM] CWE-468 kernel: net: ipv4: fix ARM64 alignment fault in multipath hash seed
kernel: net: ipv4: fix ARM64 alignment fault in multipath hash seed
In the Linux kernel, the following vulnerability has been resolved:
net: ipv4: fix ARM64 alignment fault in multipath hash seed
`struct sysctl_fib_multipath_hash_seed` contains two u32 fields
(user_seed and mp_seed), making it an 8-byte structure with a 4-byte
alignment requirement.
In `fib_multipath_hash_from_keys()`, the code evaluates the entire
struct atomically via `READ_ONCE()`:
mp_seed = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_seed).mp_seed;
While this silently works on GCC by falling back to unaligned regular
loads which the ARM64 kernel tolerates, it causes a fatal kernel panic
when compiled with Clang and LTO enabled.
Commit e35123d83ee3 ("arm64: lto: Strengthen READ_ONCE() to acquire
when CONFIG_LTO=y") s
Debian
CVE-2026-23316: linux - In the Linux kernel, the following vulnerability has been resolved: net: ipv4: ...
vendor_debian·2026
CVE-2026-23316 [LOW] CVE-2026-23316: linux - In the Linux kernel, the following vulnerability has been resolved: net: ipv4: ...
In the Linux kernel, the following vulnerability has been resolved: net: ipv4: fix ARM64 alignment fault in multipath hash seed `struct sysctl_fib_multipath_hash_seed` contains two u32 fields (user_seed and mp_seed), making it an 8-byte structure with a 4-byte alignment requirement. In `fib_multipath_hash_from_keys()`, the code evaluates the entire struct atomically via `READ_ONCE()`: mp_seed = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_seed).mp_seed; While this silently works on GCC by falling back to unaligned regular loads which the ARM64 kernel tolerates, it causes a fatal kernel panic when compiled with Clang and LTO enabled. Commit e35123d83ee3 ("arm64: lto: Strengthen READ_ONCE() to acquire when CONFIG_LTO=y") strengthens `READ_ONCE()` to use Load-Acquire instructions (`ldar` / `
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-23316 kernel: net: ipv4: fix ARM64 alignment fault in multipath hash seed
bugzilla·2026-03-25·CVSS 5.5
CVE-2026-23316 [MEDIUM] CVE-2026-23316 kernel: net: ipv4: fix ARM64 alignment fault in multipath hash seed
CVE-2026-23316 kernel: net: ipv4: fix ARM64 alignment fault in multipath hash seed
In the Linux kernel, the following vulnerability has been resolved:
net: ipv4: fix ARM64 alignment fault in multipath hash seed
`struct sysctl_fib_multipath_hash_seed` contains two u32 fields
(user_seed and mp_seed), making it an 8-byte structure with a 4-byte
alignment requirement.
In `fib_multipath_hash_from_keys()`, the code evaluates the entire
struct atomically via `READ_ONCE()`:
mp_seed = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_seed).mp_seed;
While this silently works on GCC by falling back to unaligned regular
loads which the ARM64 kernel tolerates, it causes a fatal kernel panic
when compiled with Clang and LTO enabled.
Commit e35123d83ee3 ("arm64: lto: Strengthen READ_ONCE() to acquire
Wiz
CVE-2026-23316 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz
CVE-2026-23316 CVE-2026-23316 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-23316 :
Linux Kernel vulnerability analysis and mitigation
In the Linux kernel, the following vulnerability has been resolved:
net: ipv4: fix ARM64 alignment fault in multipath hash seed
struct sysctl_fib_multipath_hash_seed
fib_multipath_hash_from_keys()
READ_ONCE()
mp_seed = READ_ONCE(net->ipv4.sysctl_fib_multipath_hash_seed).mp_seed;
While this silently works on GCC by falling back to unaligned regular
loads which the ARM64 kernel tolerates, it causes a fatal kernel panic
when compiled with Clang and LTO enabled.
READ_ONCE()
ldar
ldapr
ldar
ldar
READ_ONCE()
u32
ldar Wn
WRITE_ONCE()
proc_fib_multipath_hash_set_seed()
str
WRITE_ONCE()
READ_ONCE()
user_seed
proc_fib_multipath_hash_seed()
Source : NVD
Published March 25, 2026
CNA Score N/A
Affected Tec
2026-03-25
Published