CVE-2026-99283

netfilter: conntrack: tcp: use UNACK timeout for non-closing RST packets

Products / packages Linux

Published 07/11/2026, 20:14:11 UTC

Severity and exploitation

Not in CISA KEVNo CVSS score

KEV coverage does not rule out exploitation.

KEV checked 14/11/2026, 21:20:32 UTC

Severity

unknown

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Not established by this record

Missing evidence does not mean no public exploit exists.

Remediation

Fix status not established

No structured fix or guidance is available here. Check the latest publisher advisory.

What this means

In the Linux kernel, the following vulnerability has been resolved:

Source excerpt · Linux

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

Linux · Linux

Linux

5 ranges

Linux version evidence

Check a product version

Compare with this publisher’s ranges. This does not inspect your installation.

affected

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 → before 4d39a039d0b7737f8475c2431f18572b3b186a3b

git versions

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 → before 0c6d33329960b2d884a399196c8403643d8a9de6

git versions

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 → before bf80e6802273a900311b44e47c9b1a59c6d2473c

git versions

0 → before 6.12.117

semver versions

0 → before 6.18.61

semver versions

Other versions: unaffected

Linux · Linux

Linux

3 ranges

Linux version evidence

Check a product version

Compare with this publisher’s ranges. This does not inspect your installation.

unaffected

6.12.117 → through 6.12.*

semver versions

6.18.61 → through 6.18.*

semver versions

7.3 → through *

original_commit_for_fix versions

Other versions: affected

Automatic dependency matching is unavailable for this record. Use the product evidence and publisher’s instructions to check your installation.

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

No structured fix or remediation guidance is available here. Check the full source description and vendor’s latest advisory for a patch or workaround; do not assume another version is safe.

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.

Original source description

Read the full publisher description

In the Linux kernel, the following vulnerability has been resolved:

netfilter: conntrack: tcp: use UNACK timeout for non-closing RST packets

Commit be0502a3f2e9 ("netfilter: conntrack: tcp: only close if RST matches exact sequence") keeps an established conntrack entry in ESTABLISHED when an in-window RST does not match the expected sequence number exactly, so the endpoint can validate the RST with a challenge ACK.

The timeout selection nevertheless uses the CLOSE timeout for every RST packet. The bug is that timeout selection is based on the packet type, not on the state transition result: even when RST validation keeps new_state in ESTABLISHED, the timeout is still forced to TCP_CONNTRACK_CLOSE.

Linux TCP independently rate limits challenge ACKs per socket. A second non-exact RST can therefore arrive after the first challenge ACK has restored the timeout but before the rate limit expires. The second RST lowers the timeout to 10 seconds again while the endpoint suppresses the second challenge ACK, allowing the conntrack entry to expire while both TCP endpoints remain established.

Using the ESTABLISHED timeout for such RSTs would avoid this short expiration window, but it could also retain stale entries for the five-day default because conntrack cannot reliably match the endpoint's exact TCP state.

Use the UNACK timeout for RST packets that leave the conntrack entry in TCP_CONNTRACK_ESTABLISHED. Exact-match RSTs and accepted RST packet trains still fall through to timeouts[new_state], which preserves the CLOSE timeout when conntrack accepts the RST as closing the flow.

This avoids the aggressive 10-second expiration window for non-exact RSTs while preserving the short timeout for RSTs that conntrack accepts as closing the flow.

References

3 sources

git.kernel.org/stable/c/4d39a039d0b7737f8475c2431f18572b3b186a3b

Source referenceLinux

git.kernel.org/stable/c/0c6d33329960b2d884a399196c8403643d8a9de6

Source referenceLinux

git.kernel.org/stable/c/bf80e6802273a900311b44e47c9b1a59c6d2473c

Source referenceLinux

Inside the record

Evidence available

Package identity · not supplied

Version evidence

Remediation guidance · not supplied

Weakness classification · not supplied

Additional publishers · not supplied

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-99283

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Environment requirements

These conditions apply together as specified by the publisher. A matching product name alone does not establish exposure.

Linux · platform conditions

Any condition may hold

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive):

After:

Through (inclusive):

Before: 6.12.117

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive):

After:

Through (inclusive):

Before: 6.18.61

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive):

After:

Through (inclusive):

Before: 7.3

Applicability preview

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Contributing organizations · 1

Linux

Assigning organization

2026-11-10

Timeline

All times UTC

7 Nov 2026, 20:14
Advisory published
Publication date supplied by the source.
10 Nov 2026, 18:15
Source updated
Latest modification date supplied by the source.
10 Nov 2026, 18:25
Last imported by cve.new
Latest catalog import, not the date we first saw this advisory.

What changed

Follow changes

CVE · CVE-2026-992832026-11-10

Observed 2026-11-10T18:25:58.868Z · upstream updated 2026-11-10T18:15:30.084Z

Product or version evidence changed

before

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after

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        "versionType": "semver"
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References changed

before

[
  "https://git.kernel.org/stable/c/0c6d33329960b2d884a399196c8403643d8a9de6",
  "https://git.kernel.org/stable/c/bf80e6802273a900311b44e47c9b1a59c6d2473c"
]

after

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  "https://git.kernel.org/stable/c/bf80e6802273a900311b44e47c9b1a59c6d2473c"
]

Environment requirements changed

before

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after

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Large field values are marked as truncated previews. Original source snapshots remain retained.

Showing up to 50 most recent observed changes.

Reading the signals

Severity · CVSS: Technical impact and attack conditions. No numeric assessment supplied.
Observed exploitation · KEV: An absent or unavailable KEV listing does not establish that exploitation has not occurred.
Predicted exploitation · EPSS: No EPSS estimate available in this record.

Record identifiers

Aliases: None recorded

Source evidence

Request a correction or dispute

Start with the assigning organization for this record. Include the CVE ID, the disputed information, and supporting evidence. A dispute does not itself reject a record.

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CVE CVE-2026-99283

Enrichment coverage

NVDNo result

Checked 07/11/2026, 20:30:31 UTC

GHSANo result

Checked 07/11/2026, 20:30:31 UTC

EUVDNo result

Checked 07/11/2026, 20:30:31 UTC

EPSSNo result

Checked 07/11/2026, 20:30:31 UTC

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netfilter: conntrack: tcp: use UNACK timeout for non-closing RST packets

Severity and exploitation

What this means

Attack conditions

Affected versions

Linux

affected

unaffected

unknown

Linux

affected

unaffected

unknown

What to do

Public exploit evidence

Original source description

References

Inside the record

Evidence available

Original records

Environment requirements

Timeline

Advisory published

Source updated

Last imported by cve.new

What changed