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NVD / CVE Program· CNA Linux

CVE-2023-53686: net/handshake: fix null-ptr-deref in handshake_nl_done_doit()

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.13% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 82ba0ff7bf0483d962e592017bef659ae022d754, 93d69f18edcca282351394c5870bec24cc99d745.

Low priority for now. Upgrade to Linux Linux 82ba0ff7bf0483d962e592017bef659ae022d754, 93d69f18edcca282351394c5870bec24cc99d745 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: net/handshake: fix null-ptr-deref in handshake_nl_done_doit() We should not call trace_handshake_cmd_done_err() if socket lookup has failed. Also we should call trace_handshake_cmd_done_err() before releasing the file, otherwise dereferencing sock->sk can return garbage. This also reverts 7afc6d0a107f ("net/handshake: Fix uninitialized local variable") Unable to handle kernel paging request at virtual address dfff800000000003 KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f] Mem abort info: ESR = 0x0000000096000005 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x05: level 1 translation fault Data abort info: ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [dfff800000000003] address between user and kernel address ranges Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 5986 Comm: syz-executor292 Not tainted 6.5.0-rc7-syzkaller-gfe4469582053 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023 pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : handshake_nl_done_doit+0x198/0x9c8 net/handshake/netlink.c:193 lr : handshake_nl_done_doit+0x180/0x9c8 sp : ffff800096e37180 x29: ffff800096e37200 x28: 1ffff00012dc6e34 x27: dfff800000000000 x26: ffff800096e373d0 x25: 0000000000000000 x24: 00000000ffffffa8 x23: ffff800096e373f0 x22: 1ffff00012dc6e38 x21: 0000000000000000 x20: ffff800096e371c0 x19: 0000000000000018 x18: 0000000000000000 x17: 0000000000000000 x16: ffff800080516cc4 x15: 0000000000000001 x14: 1fffe0001b14aa3b x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000003 x8 : 0000000000000003 x7 : ffff800080afe47c x6 : 0000000000000000 x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff800080a88078 x2 : 0000000000000001 x1 : 00000000ffffffa8 x0 : 0000000000000000 Call trace: handshake_nl_done_doit+0x198/0x9c8 net/handshake/netlink.c:193 genl_family_rcv_msg_doit net/netlink/genetlink.c:970 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1050 [inline] genl_rcv_msg+0x96c/0xc50 net/netlink/genetlink.c:1067 netlink_rcv_skb+0x214/0x3c4 net/netlink/af_netlink.c:2549 genl_rcv+0x38/0x50 net/netlink/genetlink.c:1078 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x660/0x8d4 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x834/0xb18 net/netlink/af_netlink.c:1914 sock_sendmsg_nosec net/socket.c:725 [inline] sock_sendmsg net/socket.c:748 [inline] ____sys_sendmsg+0x56c/0x840 net/socket.c:2494 ___sys_sendmsg net/socket.c:2548 [inline] __sys_sendmsg+0x26c/0x33c net/socket.c:2577 __do_sys_sendmsg net/socket.c:2586 [inline] __se_sys_sendmsg net/socket.c:2584 [inline] __arm64_sys_sendmsg+0x80/0x94 net/socket.c:2584 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x58/0x16c arch/arm64/kernel/entry-common.c:678 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591 Code: 12800108 b90043e8 910062b3 d343fe68 (387b6908)

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Oct 7, 2025
Updated
Oct 28, 2026
EPSS
0.1% · 2th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel6.4 and later · before 6.5.4

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 6.4affected
    • 3b3009ea8abb713b022d94fba95ec270cf6e7eae and later · before 93d69f18edcca282351394c5870bec24cc99d745affected · git
    • 3b3009ea8abb713b022d94fba95ec270cf6e7eae and later · before 82ba0ff7bf0483d962e592017bef659ae022d754affected · git
    • before 6.4not affected · semver
    • 6.5.4 and later · up to and including 6.5.*not affected · semver
    • 6.6 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:13linuxbefore 6.5.6-16.5.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2023-53684Oct 7, 2025 · xfrm: Zero padding when dumping algos and encap
    22Monitor
  • ← EarlierCVE-2023-53685Oct 7, 2025 · tun: Fix memory leak for detached NAPI queue.
    22Monitor
  • Later →CVE-2023-53687Oct 7, 2025 · tty: serial: samsung_tty: Fix a memory leak in s3c24xx_serial_getclk() when iterating clk
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux82ba0ff7bf0483d962e592017bef659ae022d754Vendor (CNA)
Linux Linux93d69f18edcca282351394c5870bec24cc99d745Vendor (CNA)
debian:linux6.5.6-1 · Debian:13Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records