Linux Kernel up to 7.2.5 lwt_bpf neigh_hh_output hard_header_len buffer overflow

CVSS Meta Temp Score
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CTI Interest Score
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7.2$5k-$25k0.00-

Summaryinfo

A vulnerability described as critical has been identified in Linux Kernel up to 7.2.5. This vulnerability affects the function neigh_hh_output of the component lwt_bpf. Executing a manipulation of the argument hard_header_len can lead to buffer overflow. The identification of this vulnerability is CVE-2026-90160. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 7.2.5. This vulnerability affects the function neigh_hh_output of the component lwt_bpf. The manipulation of the argument hard_header_len with an unknown input leads to a buffer overflow vulnerability. The CWE definition for the vulnerability is CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. As an impact it is known to affect availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: lwt_bpf: Restore reserved headroom after xmit program ip_finish_output2() expands an skb to LL_RESERVED_SPACE(dev) before LWT xmit. An LWT_XMIT BPF program can then modify the skb head and still return BPF_OK, so bpf_xmit() rechecks the remaining headroom before the skb continues to neighbour output. That recheck uses dst->dev->hard_header_len. This is not enough for the neighbour cached-header path: neigh_hh_output() copies the cached hardware header using the aligned hh_cache size, HH_DATA_MOD for short headers or HH_DATA_ALIGN(hh_len) otherwise. On Ethernet, hard_header_len is 14 but the cached copy needs 16 bytes. If an LWT_XMIT BPF program calls bpf_skb_change_head(skb, 1, 0), the skb can still have 15 bytes of headroom after the program. The existing check accepts that, after which neigh_hh_output() hits its headroom warning and drops the skb. Use LL_RESERVED_SPACE(dst->dev) in the post-BPF headroom check to match the reservation made before LWT xmit.

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-90160 since 09/11/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 09/17/2026).

Upgrading to version 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch 753e5cdcca5474d230d62bb3489e5168ab27c272/c488071c3441fa34f5a87cd6c12ce2cc6304f20e/a38c0eb447e2dd0120a2ebcdba470f9505ac8907/de2b2004e16f2930eb689175e2c1998b0a68d499/7d043e24520a273c362be5dd7d9c82796879a49b/7cf561843ed0ad57501892a65abb77957e6c800f/179a5b2171573d94a25c9aa8e1c9f9ac352ad316/5fe7007aed9ad069b2bd77e5d0c875c64f5c0269 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.2

VulDB Base Score: 7.5
VulDB Temp Score: 7.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.270/5.15.221/6.1.188/6.6.157/6.12.110/6.18.52/7.2.6/7.3-rc1
Patch: 753e5cdcca5474d230d62bb3489e5168ab27c272/c488071c3441fa34f5a87cd6c12ce2cc6304f20e/a38c0eb447e2dd0120a2ebcdba470f9505ac8907/de2b2004e16f2930eb689175e2c1998b0a68d499/7d043e24520a273c362be5dd7d9c82796879a49b/7cf561843ed0ad57501892a65abb77957e6c800f/179a5b2171573d94a25c9aa8e1c9f9ac352ad316/5fe7007aed9ad069b2bd77e5d0c875c64f5c0269

Timelineinfo

09/11/2026 CVE reserved
09/17/2026 +6 days Advisory disclosed
09/17/2026 +0 days VulDB entry created
09/17/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-90160 (🔒)
GCVE (CVE): GCVE-0-2026-90160
GCVE (VulDB): GCVE-100-406684

Entryinfo

Created: 09/17/2026 20:16
Changes: 09/17/2026 20:16 (60)
Complete: 🔍
Cache ID: 216::103

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