VulnerabilityPublished 6 Nov 2026

CVE-2026-87045: zephyrproject zephyr · Memory-safety

Affects zephyrproject zephyrSource CVE Database V5

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Not known to be exploited · CVSS 7.5 High : upgrade to 4.5.0 or 4.3.2 soon.

Data as of 6 Nov 2026, 14:51 UTC

CVSS 3.1 base score

7.5High

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

Thin evidence

One scorer or none

CVSS scores by source
CNA (zephyr)	CVSS 3.1	7.5

Patch: Available – fixed in 4.5.0, 4.3.2

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 6 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 6 Nov 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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 zephyrproject zephyr to 4.5.0 or 4.3.2.

Affected software

Product	Affected	Fixed in
zephyrprojectzephyr	Affected >=4.4.0 <4.5.0	Fixed in 4.5.0
zephyrprojectzephyr	Affected >=4.1.0 <4.3.2	Fixed in 4.3.2
GitHubzephyr`pkg:github/zephyr`Other threats	Affected >=4.1.0 <4.3.2 >=4.4.0 <4.5.0	Fixed in 4.3.2 4.5.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available in Zephyr versions 4.3.2 and 4.5.0. Users should upgrade to these or later versions to remediate this vulnerability. No other mitigation is required as the vulnerability is fully addressed by the official patches.

Description

CVE-2026-87045 is a memory safety vulnerability in the HTTP/2 server component of Zephyr (subsys/net/lib/http/http_server_http2.c). It occurs because the server clears the stream binding at the start of every frame, but CONTINUATION frames do not open a new stream, leaving client->current_stream unset. Subsequent code writes through this NULL pointer, causing a crash. This can be triggered remotely without authentication by sending a CONTINUATION frame after the client preface requesting any unregistered path. The impact is a denial of service due to system halt. There is no confidentiality or integrity impact. The vulnerability affects Zephyr versions >=4.1.0 <4.3.2 and >=4.4.0 <4.5.0 and is fixed in versions 4.3.2 and 4.5.0.

Impact

An unauthenticated remote attacker can cause a denial of service by triggering a NULL pointer write in the HTTP/2 server, leading to a system halt. There is no impact on confidentiality or integrity since the attacker cannot control the target address or written value. The vulnerability affects any device running the vulnerable Zephyr HTTP/2 server, including those accepting cleartext HTTP/2 connections.

Summary

The HTTP/2 server in Zephyr improperly handles CONTINUATION frames by unconditionally clearing the current stream binding without rebinding it for CONTINUATION frames, which do not open new streams. This leads to NULL pointer dereferences when processing header blocks, specifically when responding to unregistered resources or unsupported methods, or when handling certain dynamic resource requests. This flaw allows any unauthenticated peer capable of reaching the server to trigger a write to a NULL pointer, causing a system fault and halting the device. The vulnerability is exploitable over cleartext HTTP/2 (h2c) and does not require TLS. The flaw is present in Zephyr versions >=4.1.0 <4.3.2 and >=4.4.0 <4.5.0 and fixed in 4.3.2 and 4.5.0.

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What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Nov 2026, 14:51 UTC

Technical details

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