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NVD / CVE Program· CNA Linux

CVE-2023-53600: tunnels: fix kasan splat when generating ipv4 pmtu error

Noroxi assessment

Priority: Monitor (action score 28/100)

  • 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: 0.29% (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.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 5850c391fd7e25662334cb3cbf29a62bcbff1084, 6a7ac3d20593865209dceb554d8b3f094c6bd940, da5f42a6e7485fbb7a6dbd6a2b3045e19e4df5cc.
  • Severity is disputed: the assigning authority (CNA) scores it 9.1, NVD 7.1.

Low priority for now. Upgrade to Linux Linux 5850c391fd7e25662334cb3cbf29a62bcbff1084, 6a7ac3d20593865209dceb554d8b3f094c6bd940, da5f42a6e7485fbb7a6dbd6a2b3045e19e4df5cc 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: tunnels: fix kasan splat when generating ipv4 pmtu error If we try to emit an icmp error in response to a nonliner skb, we get BUG: KASAN: slab-out-of-bounds in ip_compute_csum+0x134/0x220 Read of size 4 at addr ffff88811c50db00 by task iperf3/1691 CPU: 2 PID: 1691 Comm: iperf3 Not tainted 6.5.0-rc3+ #309 [..] kasan_report+0x105/0x140 ip_compute_csum+0x134/0x220 iptunnel_pmtud_build_icmp+0x554/0x1020 skb_tunnel_check_pmtu+0x513/0xb80 vxlan_xmit_one+0x139e/0x2ef0 vxlan_xmit+0x1867/0x2760 dev_hard_start_xmit+0x1ee/0x4f0 br_dev_queue_push_xmit+0x4d1/0x660 [..] ip_compute_csum() cannot deal with nonlinear skbs, so avoid it. After this change, splat is gone and iperf3 is no longer stuck.

HighCVSS 7.1 · v3.1—No exploit Fix available
Published
Oct 4, 2025
Updated
Oct 15, 2026
EPSS
0.2% · 22th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.1
CNA · Linux
9.1
2.0 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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 kernel5.9 and later · before 5.10.191
  • linux linux kernel5.11 and later · before 5.15.127
  • linux linux kernel5.16 and later · before 6.1.46
  • linux linux kernel6.2 and later · before 6.4.11
  • linux linux kernel6.5

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

    • 5.9affected
    • 4cb47a8644cc9eb8ec81190a50e79e6530d0297f and later · before 5850c391fd7e25662334cb3cbf29a62bcbff1084affected · git
    • 4cb47a8644cc9eb8ec81190a50e79e6530d0297f and later · before e95808121953410db8c59f0abfde70ac0d34222caffected · git
    • 4cb47a8644cc9eb8ec81190a50e79e6530d0297f and later · before da5f42a6e7485fbb7a6dbd6a2b3045e19e4df5ccaffected · git
    • 4cb47a8644cc9eb8ec81190a50e79e6530d0297f and later · before fe6a9f7516735be9fdabab00e47ef7a3403a174daffected · git
    • 4cb47a8644cc9eb8ec81190a50e79e6530d0297f and later · before 6a7ac3d20593865209dceb554d8b3f094c6bd940affected · git
    • before 5.9not affected · semver
    • 5.10.191 and later · up to and including 5.10.*not affected · semver
    • 5.15.127 and later · up to and including 5.15.*not affected · semver
    • 6.1.46 and later · up to and including 6.1.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.52-16.1.52-1
Debian:13linuxbefore 6.4.11-16.4.11-1

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-2023-53589Oct 4, 2025 · wifi: iwlwifi: mvm: don't trust firmware n_channels
    22Monitor
  • ← EarlierCVE-2023-53598Oct 4, 2025 · bus: mhi: host: Range check CHDBOFF and ERDBOFF
    22Monitor
  • Later →CVE-2023-53606Oct 4, 2025 · nfsd: clean up potential nfsd_file refcount leaks in COPY codepath
    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 Linux5850c391fd7e25662334cb3cbf29a62bcbff1084Vendor (CNA)
Linux Linux6a7ac3d20593865209dceb554d8b3f094c6bd940Vendor (CNA)
Linux Linuxda5f42a6e7485fbb7a6dbd6a2b3045e19e4df5ccVendor (CNA)
Linux Linuxe95808121953410db8c59f0abfde70ac0d34222cVendor (CNA)
Linux Linuxfe6a9f7516735be9fdabab00e47ef7a3403a174dVendor (CNA)
debian:linux6.1.52-1 · Debian:12Package 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
high · data can be read
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
High
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

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

ATT&CK techniques

—

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (4 more)

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

All records