VulnerabilityPublished 13 Aug 2026Updated 9 Nov 2026

CVE-2026-45243: Summarize < 0.15.1 Browser Extension Missing Authorization via Content Script

Affects summarizeSource GCVE Database

Compare

Authoritative record:CVE-2026-45243· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium : upgrade to 0.15.1 when convenient.

Data as of 9 Nov 2026, 19:37 UTC

CVSS 4.0 base score

5.3Medium

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

Thin evidence

One scorer or none

CVSS scores by source
CNA (VulnCheck)	CVSS 4.0	5.3
CNA (VulnCheck)	CVSS 3.1	6.1

Patch: Available – fixed in 0.15.1

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

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: Low
Subsequent system availability: None

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: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Subsequent 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.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 18 May 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 9 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 summarize to 0.15.1.

Patches and advisories

Affected software

Product	Affected	Fixed in
Homebrewsummarize`pkg:brew/summarize`Other threats	Affected >=0.12.0 <0.15.1	Fixed in 0.15.1

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

AI-suggested

Upgrade the Summarize browser extension to version 0.15.1 or later, where the missing authorization vulnerability in the content script has been fixed. Refer to the official patches at https://github.com/steipete/summarize/commit/357544063af535bd574752622f9eb94be33ee5fd and https://github.com/steipete/summarize/pull/222 for details. No other specific mitigations are indicated.

Description

Summarize browser extension versions prior to 0.15.1 contain a missing authorization vulnerability in the content script's window.postMessage bridge. This flaw allows malicious web pages to perform unauthorized operations on automation artifacts within the affected tab by simulating runtime messages with spoofed sender identifiers. The vulnerability enables attackers to list, read, create, overwrite, or delete these artifacts without proper authorization checks. A fix is available in version 0.15.1.

Impact

Attackers can exploit this vulnerability to perform unauthorized operations on automation artifacts within the context of the affected browser tab. This may lead to unauthorized data access or manipulation of automation-related data. However, the vulnerability requires user interaction (UI:P) and network attack vector (AV:N), and no privileges or user interaction beyond visiting a malicious page are required. No known exploits in the wild have been reported.

References

Community reviews

Loading reviews…