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CVE-2026-53078
bpf: Fix same-register dst/src OOB read and pointer leak in sock_ops
Published 2026-06-24 (4 months ago) by the Linux kernel CNA. Subsystem net/core. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-53078 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixedDLA-4841-1 · 2026-10-17 · text | 6.1.190-1 | Update the kernel and reboot. DLA-4841-1 shipped the fix on 2026-10-17, in 6.1.190-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6415-1 · 2026-08-06 · text | 6.12.101-1 | Update the kernel and reboot. DSA-6415-1 shipped the fix on 2026-08-06, in 6.12.101-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.0.10-1 | Update the kernel and reboot. Fixed in 7.0.10-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.0.10-1 | Update the kernel and reboot. Fixed in 7.0.10-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4745-1 · 2026-08-18 · text | 6.12.101-1~deb12u1 | Update the kernel and reboot. DLA-4745-1 shipped the fix on 2026-08-18, in 6.12.101-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
When a BPF sock_ops program accesses ctx fields with dst_reg == src_reg, the SOCK_OPS_GET_SK() and SOCK_OPS_GET_FIELD() macros fail to zero the destination register in the !fullsock / !locked_tcp_sock path. Both macros borrow a temporary register to check is_fullsock / is_locked_tcp_sock when dst_reg == src_reg, because dst_reg holds the ctx pointer. When the check is false (e.g., TCP_NEW_SYN_RECV state with a request_sock), dst_reg should be zeroed but is not, leaving the stale ctx pointer: - SOCK_OPS_GET_SK: dst_reg retains the ctx pointer, passes NULL checks as PTR_TO_SOCKET_OR_NULL, and can be used as a bogus socket pointer, leading to stack-out-of-bounds access in helpers like bpf_skc_to_tcp6_sock(). - SOCK_OPS_GET_FIELD: dst_reg retains the ctx pointer which the verifier believes is a SCALAR_VALUE, leaking a kernel pointer. Fix both macros by: - Changing JMP_A(1) to JMP_A(2) in the fullsock path to skip the added instruction. - Adding BPF_MOV64_IMM(si->dst_reg, 0) after the temp register restore in the !fullsock path, placed after the restore because dst_reg == src_reg means we need src_reg intact to read ctx->temp.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
net/core/filter.c
- What this is
- BPF [GENERAL] (Safe Dynamic Programs and Tools)MAINTAINERS section matched on net/core/filter.c · bpf@vger.kernel.org · Supported
Show whether Debian builds this, per release
Debian builds this code. Every release below compiles the affected file into the kernels it ships.
- bookworm, trixie, forky, sid, bookworm · linux-6.12y
- y
- built into the kernel image on every flavour - only a patch removes it
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS Debian linux-config packages
Signals
- Published
- 2026-06-24 (4 months ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.12%, higher than 1.7% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- net/core
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.9 | 5.10.270 | db1200ec2c3d |
| 5.9 | 5.15.221 | 4c1c5efd9d1d |
| 5.9 | 6.1.188 | 0e6b30657bbc |
| 5.9 | 6.6.157 | 64eaf4ecda00 |
| 5.9 | 6.12.101 | 2a2c98141e0a |
| 5.9 | 6.18.42 | 22400725de07 |
| 5.9 | 7.0.10 | 18e3ffde1822 |
| 5.9 | 7.1 | 10f86a2a5c91 |
| 5.7.18 | 0 | 0 |
| 5.8.4 | 0 | 0 |
| 5.4.61 | 0 | 0 |
| 5.7.18 | 0 | 0 |
| 5.8.4 | 0 | 0 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4841-1 | 2026-10-17 | bookworm 6.1.190-1 | tracker |
| DLA-4745-1 | 2026-08-18 | bookworm 6.12.101-1~deb12u1 | tracker |
| DSA-6415-1 | 2026-08-06 | trixie 6.12.101-1 | tracker |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- Exploitation requires loading and attaching a crafted BPF_PROG_TYPE_SOCK_OPS program through the local bpf() interface. Remote TCP traffic can trigger an attached program, but cannot by itself create the malicious program.
- AC:LAttack complexity, low
- The attacker controls the BPF bytecode pattern and can reliably trigger non-fullsock/request_sock sock_ops callbacks with local TCP activity. No uncontrolled race or rare runtime condition is required.
- PR:LPrivileges required, low
- Loading/attaching sock_ops BPF requires BPF and net-admin style privileges, but these can be available to a local user through user-namespace/BPF-token delegation in plausible deployments. Under the required overestimate rule this is Low rather than High.
- UI:NUser interaction, none
- No victim action is needed after the attacker loads and attaches the crafted sock_ops program. The attacker can trigger the callback path directly.
- S:UScope, unchanged
- The impact is within the same kernel security authority. This is not a VM escape, IOMMU bypass, or cross-scope boundary violation.
- C:HConfidentiality impact, high
- The bug leaks a kernel context pointer as a scalar and lets it be used as a bogus socket pointer. Helper dereferences can perform kernel stack out-of-bounds reads, so confidentiality impact is High.
- I:HIntegrity impact, high
- The bogus verifier-approved socket pointer can reach helpers that mutate socket-associated state, creating plausible kernel memory corruption from a misinterpreted stack object. With uncertainty required to resolve upward, integrity impact is High.
- A:HAvailability impact, high
- The same bogus pointer path can cause kernel stack out-of-bounds accesses and invalid helper dereferences. These can crash or panic the kernel, so availability impact is High.