VulnerabilityPublished 23 Oct 2026Updated 24 Oct 2026

CVE-2026-99081: Linux kernel · bnxt_en: fix DMA mapping length for padded small packets

Affects Linux kernelSource CVE Database V5

Not known to be exploited · CVSS 7.5 High · fixed in fbd977e513971ccb4f0762a7f59eac500e474f89 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:30 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 39% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in fbd977e513971ccb4f0762a7f59eac500e474f89, cf8530a25ae92c4493e2f22981ecb46f0b66f4c8, a51d233ccd4889aadb71dace863525cc2b00271e +2

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ c0c050c58d840994ba842ad1c338a98e7c12b764, < fbd977e513971ccb4f0762a7f59eac500e474f89	Fixed in fbd977e513971ccb4f0762a7f59eac500e474f89
LinuxLinux	Affected ≥ c0c050c58d840994ba842ad1c338a98e7c12b764, < cf8530a25ae92c4493e2f22981ecb46f0b66f4c8	Fixed in cf8530a25ae92c4493e2f22981ecb46f0b66f4c8
LinuxLinux	Affected ≥ c0c050c58d840994ba842ad1c338a98e7c12b764, < a51d233ccd4889aadb71dace863525cc2b00271e	Fixed in a51d233ccd4889aadb71dace863525cc2b00271e
LinuxLinux	Affected ≥ c0c050c58d840994ba842ad1c338a98e7c12b764, < 5213f65a9667d3dd85db2e6df8f2e0516290db34	Fixed in 5213f65a9667d3dd85db2e6df8f2e0516290db34
LinuxLinux	Affected ≥ c0c050c58d840994ba842ad1c338a98e7c12b764, < 2956aca14dd2977cd08bd2ccafae3beb8b84b268	Fixed in 2956aca14dd2977cd08bd2ccafae3beb8b84b268
LinuxLinux	Affected =4.4	Fixed in–

AI-suggested

A fix is available and has been applied in specific Linux kernel commits. Users should update to a Linux kernel version that includes the fix identified by commits fbd977e513971ccb4f0762a7f59eac500e474f89, cf8530a25ae92c4493e2f22981ecb46f0b66f4c8, a51d233ccd4889aadb71dace863525cc2b00271e, 5213f65a9667d3dd85db2e6df8f2e0516290db34, or 2956aca14dd2977cd08bd2ccafae3beb8b84b268. No additional mitigations are required beyond applying the official fix.

Description

CVE-2026-99081 is a vulnerability in the Linux kernel's bnxt_en driver for Broadcom NetXtreme-E NICs. It involves incorrect DMA mapping length for padded small packets, causing the NIC's DMA engine to read beyond the mapped buffer boundary. This can trigger Intel IOMMU DMA read faults and cause transmit queue timeouts. The issue arises because the driver pads small packets to a minimum size but does not adjust the DMA mapping length accordingly, leading to DMA overruns when packets are near page boundaries. The vulnerability was introduced after a commit that changed VLAN headroom handling. It has been fixed by ensuring the skb buffer is properly padded before DMA mapping, aligning the mapped length with the actual transmitted length.

Impact

This vulnerability can cause Intel IOMMU DMA read faults due to DMA overruns when transmitting small padded packets on affected NICs. The faults lead to transmit queue timeouts and message abandonment, potentially causing network transmission disruptions or degraded network performance. There is no indication of confidentiality or integrity impact, but availability is affected due to transmit failures.

Summary

The Linux kernel bnxt_en driver had a flaw in handling DMA mapping lengths for small packets padded to a minimum size (52 bytes). The driver padded packets smaller than BNXT_MIN_PKT_SIZE but did not update the DMA mapping length from the original smaller size, causing dma_map_single() to map fewer bytes than the hardware transmitted. When the padded packet data crossed a 4KB page boundary, the NIC's DMA engine read beyond the mapped buffer, causing Intel IOMMU DMA read faults and transmit queue timeouts. This was exposed after a commit that increased VLAN headroom, shifting skb->data offsets. The fix uses skb_put_padto() to pad the skb before DMA mapping, ensuring the mapped length matches the padded packet size and preventing DMA overruns.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 09:47 UTC

Technical details

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