VulnerabilityPublished 4 Nov 2026

CVE-2026-87044: zephyrproject zephyr · Dos

Affects zephyrproject zephyrSource CVE Database V5

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Not known to be exploited · CVSS 6.5 Medium : upgrade to 4.5.0 when convenient.

Data as of 4 Nov 2026, 06:28 UTC

CVSS 3.1 base score

6.5Medium

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	6.5

Patch: Available – fixed in 4.5.0

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

Attack Vector: Adjacent
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: Adjacent: The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).
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 4 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 3 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.

Affected software

Product	Affected	Fixed in
zephyrprojectzephyr	Affected >=4.4.0 <4.5.0	Fixed in 4.5.0
GitHubzephyr`pkg:github/zephyr`Other threats	Affected >=4.4.0 <4.5.0	Fixed in 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 version 4.5.0 that ensures all error paths after successful setup call the appropriate PSA abort functions to prevent memory leaks. Users should upgrade to Zephyr 4.5.0 or later to remediate this issue. No other mitigation is required as the vulnerability is addressed by this official fix.

Description

CVE-2026-87044 is a denial-of-service vulnerability in the Zephyr project's Mbed TLS crypto shim driver. The flaw causes heap memory leaks on certain error paths during multipart cipher and AEAD operations, leading to exhaustion of the fixed-size Mbed TLS heap. An unauthenticated attacker can exploit this by sending a stream of invalid IEEE 802.15.4 frames or OSDP secure channel messages, causing repeated failures and memory leaks. This results in permanent failure of cryptographic operations until the device is rebooted. No memory corruption or data disclosure occurs. The issue is fixed in Zephyr version 4.5.0.

Impact

An unauthenticated attacker can cause a denial of service by exhausting the Mbed TLS heap through repeated failed cryptographic operations triggered by sending invalid IEEE 802.15.4 frames or OSDP secure channel messages. This leads to permanent failure of all subsequent cryptographic operations relying on the same heap, including link-layer security and TLS/DTLS, until the device is rebooted. There is no memory corruption or information disclosure; the impact is limited to availability.

Summary

The Mbed TLS crypto shim driver in Zephyr (drivers/crypto/crypto_mbedtls_shim.c) improperly handles error paths after successful psa_cipher_encrypt_setup() or psa_aead_decrypt_setup() calls by returning without calling psa_cipher_abort() or psa_aead_abort(). This omission causes heap-allocated mbedtls_aes_context objects to leak on each failed operation. With CONFIG_NET_L2_IEEE802154_SECURITY enabled, an attacker in radio range can send syntactically valid 802.15.4 frames with bogus MICs, triggering psa_aead_verify() failures and leaking memory blocks. Similarly, the CBC path is vulnerable via the OSDP secure channel when CONFIG_OSDP_SC_ENABLED is set. The fixed-size Mbed TLS heap (default 512 bytes) is exhausted quickly, causing all subsequent cryptographic allocations to fail permanently, impacting link-layer security and TLS/DTLS operations sharing the heap. The vulnerability causes availability loss but no memory corruption or information disclosure. The fix ensures all post-setup failures call the appropriate PSA abort functions before returning, preventing leaks. This vulnerability affects Zephyr versions >=4.4.0 and <4.5.0 and is fixed in 4.5.0.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Nov 2026, 06:16 UTC

Technical details

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