VulnerabilityPublished 12 Oct 2026Updated 23 Oct 2026

CVE-2026-109295: open-webui · ReDoS

Affects open-webuiSource CVE Database V5

Public exploit available · CVSS 5.3 Medium : upgrade to 0.11.4 as a priority.

Data as of 26 Oct 2026, 13:07 UTC

CVSS 4.0 base score

5.3Medium

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

EPSS

0.3% chance of exploitation in 30 days – higher than 25% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation: Proof of concept is public or traded
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-13.

Patch

Available – fixed in 0.11.4

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

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
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: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
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: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable 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.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

Disclosed: evidence found.
CVE published 12 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
CISA SSVC: proof of concept public
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

CVE ID reserved
by VulnCheck
12 Oct 202614:12 UTC, 2 hours before disclosure
CVE published
on cve.org
12 Oct 202616:04 UTC, t = 0
CISA SSVC assessment
proof of concept public
13 Oct 202618:08 UTC, 26 hours after disclosure
In Threat Radar
record ingested
26 Oct 202609:29 UTC, 14 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA SSVC, 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 open-webui to 0.11.4.

Affected software

Product	Affected	Fixed in
open-webuiopen-webui	Affected >=0.11.0 <0.11.4	Fixed in 0.11.4
PyPIopen-webui`pkg:pypi/open-webui`Other threats	Affected >=0.11.0 <0.11.4	Fixed in 0.11.4

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

AI-suggested

Upgrade Open WebUI to version 0.11.4 or later, where this vulnerability is fixed. No other mitigation or workaround is indicated.

Description

Open WebUI versions from 0.11.0 up to but not including 0.11.4 contain a regular expression denial of service (ReDoS) vulnerability. Authenticated users can exploit this flaw by providing file search patterns that cause catastrophic backtracking in regex processing, stalling server workers and blocking the event loop for approximately two seconds per repeated call. This vulnerability is fixed in version 0.11.4.

Impact

An attacker with authenticated access can cause denial of service by stalling server workers through inefficient regular expression processing. This results in server event loop blocking, degrading availability and responsiveness of the Open WebUI service. There is no indication of privilege escalation, data leakage, or remote code execution. The CVSS 4.0 base score is 5.3, indicating medium severity.

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Exploitation evidence

Timeline

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 09:50 UTC

Technical details

References

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