CVE-2026-74625Network attack vector

Host denial of service via conntrack template leak

Published Aug 22, 2026 · Updated Aug 25, 2026

Memory leak in Linux kernel 5.3 and later allows remote attackers to exhaust host memory via non-IP frames sent to a configured bridge. nf_ct_bridge_pre() replaces skb->_nfct with IP_CT_UNTRACKED without dropping a conntrack-template reference already attached by a bridge nftables ct zone set rule. Repeated non-IPv4/IPv6 traffic reaches the flaw only when that rule precedes bridge conntrack processing, and leaked slab memory can stop the host.

CVSS severity7.5
High
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in Linux kernel 5.3 and later allows remote attackers to exhaust host memory via non-IP frames sent to a configured bridge. nf_ct_bridge_pre() replaces skb->_nfct with IP_CT_UNTRACKED without dropping a conntrack-template reference already attached by a bridge nftables ct zone set rule. Repeated non-IPv4/IPv6 traffic reaches the flaw only when that rule precedes bridge conntrack processing, and leaked slab memory can stop the host.

The record

CVE
CVE-2026-74625
Published
Aug 22, 2026
Updated
Aug 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-772, CWE-401, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3c171f496ef57774f8e5d509923372549734877f <46d559f00b1ab1d114f92d2f16c5ef0093b3b9dd
  2. Affected versionversion=3c171f496ef57774f8e5d509923372549734877f <6ea88401e10e04e0b3bb7a7adea54932fb60b93b
  3. Affected versionversion=3c171f496ef57774f8e5d509923372549734877f <7cff440d702616022769f2643168d7f9820547a0
  4. Affected versionversion=3c171f496ef57774f8e5d509923372549734877f <bd7b16494dacf87e9336a1dcfdada83b9e40edd6
  5. Affected versionversion=3c171f496ef57774f8e5d509923372549734877f <c58d34fe8b7e47bb0b350a7625023b1261342be5
  6. Affected versionversion=3c171f496ef57774f8e5d509923372549734877f <d45cc8020d7c0a9f01dee42ff5c40bc14c9af72f
  7. Affected versionversion=3c171f496ef57774f8e5d509923372549734877f <daa6e070f8e1e7a4dddec8b64ca37663f8cda917
  8. Affected versionversion=3c171f496ef57774f8e5d509923372549734877f <fc90df37540627d092af770215fb4b7befe9409b
  9. Affected versionversion=5.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3c171f496ef57774f8e5d509923372549734877f <46d559f00b1ab1d114f92d2f16c5ef0093b3b9dd; version=3c171f496ef57774f8e5d509923372549734877f <6ea88401e10e04e0b3bb7a7adea54932fb60b93b; version=3c171f496ef57774f8e5d509923372549734877f <7cff440d702616022769f2643168d7f9820547a0; version=3c171f496ef57774f8e5d509923372549734877f <bd7b16494dacf87e9336a1dcfdada83b9e40edd6; version=3c171f496ef57774f8e5d509923372549734877f <c58d34fe8b7e47bb0b350a7625023b1261342be5; version=3c171f496ef57774f8e5d509923372549734877f <d45cc8020d7c0a9f01dee42ff5c40bc14c9af72f; version=3c171f496ef57774f8e5d509923372549734877f <daa6e070f8e1e7a4dddec8b64ca37663f8cda917; version=3c171f496ef57774f8e5d509923372549734877f <fc90df37540627d092af770215fb4b7befe9409b; version=5.3

Published CVSS scores

7.5UbuntuCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5Linux CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-772Missing Release of Resource after Effective Lifetime
CWE-401Missing Release of Memory after Effective Lifetime
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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