VulnerabilityPublished 13 Aug 2026Updated 4 Nov 2026

CVE-2026-54279: aiohttp · Host-Only Cookies Become Domain Cookies After CookieJar Persistence

Affects kimi-cliSource GCVE Database

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Authoritative record:CVE-2026-54279· Low 1.3

Not known to be exploited · CVSS 1.3 Low.

Data as of 4 Nov 2026, 06:59 UTC

CVSS 4.0 base score

1.3Low

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

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N/E:U

Base metrics

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: Passive
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: Low
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: Unreported

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, 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: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: Passive: Successful exploitation of this vulnerability requires limited interaction by the targeted user with the vulnerable system and the attacker’s payload. These interactions would be considered involuntary and do not require that the user actively subvert protections built into the vulnerable system.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Subsequent System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: Unreported: Based on threat intelligence sources each of the following must apply: · No knowledge of publicly available proof-of-concept · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Jun 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

Affected software

Product	Affected	Fixed in
Homebrewkimi-cli`pkg:brew/kimi-cli`Other threats	Affected >=0.40	Fixed in–

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AI-suggested

A patch is available and should be applied to fix the loss of host-only cookie status during persistence. Users should update to the fixed version of the software incorporating the patch from https://github.com/aio-libs/aiohttp/commit/a329a7aacad5284f087af36103aff778746da0f2. No other mitigations are indicated by the vendor advisory.

Description

A vulnerability in aiohttp's CookieJar persistence causes host-only cookies saved and later restored from disk to lose their host-only status. This results in cookies being sent to subdomains that should not receive them, potentially exposing sensitive cookie data. The issue affects versions of the kimi-cli product from 0.40 onward. A patch is available to address this behavior.

Impact

Host-only cookies that are persisted to disk and restored may be sent to subdomains, which should not normally receive these cookies. This can lead to unintended cookie sharing across subdomains, potentially exposing session or authentication cookies to unauthorized subdomains. The impact is limited to confidentiality and integrity of cookie data within the affected application context.

Summary

The vulnerability (CVE-2026-54279) in aiohttp involves the CookieJar's save and load functionality. When host-only cookies are saved using CookieJar.save() and later restored with CookieJar.load(), they lose their host-only attribute. Consequently, these cookies may be sent to subdomains that were previously disallowed, violating cookie scope restrictions. This can lead to unintended cookie exposure across subdomains. The issue affects kimi-cli versions >=0.40. A patch fixing this behavior has been published in the aiohttp GitHub repository.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Nov 2026, 06:59 UTC

Technical details

References

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