What is CVE-2023-49105?

CVE-2023-49105 is ownCloud Improper Authentication Vulnerability. The supplied enrichment data classifies it as Auth Bypass mapped to CWE-287 Improper Authentication.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Yes: CISA KEV signal present. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

Is there a public exploit?

4 public PoC repositories reported; 1 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS, identity provider logs, authentication audit logs where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2023-49105 using CVSS 9.8, EPSS 43%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Treat as emergency remediation because CISA KEV status is present. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

CISA KEVcriticalAuth Bypasspublic exploit

CVE-2023-49105

CVE-2023-49105 — ownCloud Improper Authentication Vulnerability

Q: Is it in CISA KEV?

Yes. The supplied enrichment data lists CVE-2023-49105 in CISA KEV with required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

An issue was discovered in ownCloud owncloud/core before 10.13.1. An attacker can access, modify, or delete any file without authentication if the username of a victim is known, and the victim has no signing-key configured. This occurs because pre-signed URLs can be accepted even when no signing-key is configured for the owner of the files. The earliest affected version is 10.6.0.

Published Nov 21, 2023Updated Aug 28, 2026Sources: NVD, ownCloud (CNA), CISA, FIRST EPSS, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Confirmed

CISA KEV, listed Aug 27, 2026

EPSS

43%

ahead of 99% of scored CVEs

Affects

ownCloud

CVSS base

9.8

critical · 2 sources

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

None

none · proof-of-concept · active

Automatable

Yes

can an attacker script all four kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

The vendor's own words where we have them.

Upgrade ownCloud to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

CISA required action

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Federal deadline Aug 30, 2026 — today

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Treat as emergency remediation because CISA KEV status is present.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
ownCloud	ownCloud	—	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

High

Confidentiality

High

Integrity

High

Scope

Unchanged

Attack Complexity

Low

Attack Vector

Network

Privileges Req

None

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
9.8	CVSS 3.1	critical	3.9	5.9	MITRE (CNA), NVD
9.8	CVSS 3.1	critical	—	—	ownCloud (CNA)

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

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-287 · Improper Authentication

Read Application Data
Gain Privileges or Assume Identity
Execute Unauthorized Code or Commands

Mitigation: Use an authentication framework or library such as the OWASP ESAPI Authentication feature.::

Weakness & attack patterns

CWE-287Improper Authentication

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

CAPEC-114 · Authentication AbuseCAPEC-115 · Authentication BypassCAPEC-151 · Identity SpoofingCAPEC-194 · Fake the Source of DataCAPEC-22 · Exploiting Trust in ClientCAPEC-57 · Utilizing REST's Trust in the System Resource to Obtain Sensitive DataCAPEC-593 · Session HijackingCAPEC-633 · Token ImpersonationCAPEC-650 · Upload a Web Shell to a Web ServerCAPEC-94 · Man in the Middle Attack

T1548Abuse Elevation Control Mechanism
T1040Network Sniffing
T1185Browser Session Hijacking

CISA KEV details

CISA lists a CVE here once it has evidence of exploitation against real targets.

CISAThat month →

Listed

Aug 27, 2026

Federal deadline

Aug 30, 2026

today

Ransomware use

Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a date to argue against.

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

1 of the 2 sampled are weaponized

Exploit entries

Exploit-DB and CTI exploit indexes

Social mentions

Posts naming this CVE. Attention, not evidence of exploitation — it spikes on disclosure and decays whether or not anything is exploited.

1 more posts on this CVEShowing 5 of 6 · Who is discussing this CVE, and how loudlyUnlock free

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Search application, proxy, and WAF logs for requests touching /core.
Prioritize edge telemetry for network-reachable ownCloud.
Monitor for scanner or exploit-pattern traffic after 4 public PoC repositories were reported.

web/proxy/WAF logsapplication logsnetwork IDS/IPSidentity provider logsauthentication audit logs

Groups associated with this CVE

Groups reported in connection with this vulnerability. A reported association, not a confirmed observation of that group using it — and not scoped to any sector or campaign.

urlhttp://timelevel12.com/big73
Maltiverse URL List · Aug 15, 2026
hostnametimelevel12.com95
ThreatFox · Aug 15, 2026
hostnamesnake.zooparkko.com90
SOCRadar Threat Exchange Services · Jul 11, 2026
hostnamefine-work-team.com96
Maltiverse Domain List · Jul 27, 2026
urlhttp://fine-work-team.com/627287
Maltiverse URL List · Jul 28, 2026

1 more indicators on this CVEShowing 5 of 6 · Hashes, addresses and domains from a live threat exchangeUnlock free

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 9.8 (AV:N)
Aug 28, 2026 · NVD
Added to CISA KEV catalog
Aug 27, 2026 · CISA
2023
CVE is exploited. "nomi-sec/PoC-in-GitHub"
Dec 14, 2023 · SOCRadar CTI
CVE is exploited. "ambionics/owncloud-exploits"
Dec 11, 2023 · SOCRadar CTI
Bulletin released on MITRE.
Nov 22, 2023 · SOCRadar CTI
Bulletin released on NIST.
Nov 22, 2023 · SOCRadar CTI
Initial · CVE published
Nov 21, 2023 · NVD

Source activity

Readings a source repeats on a schedule, counted rather than listed.

13×TweetsNov 22, 2023 – Aug 29, 2026 · SOCRadar CTI
8×SvrsNov 26, 2023 – Aug 29, 2026 · SOCRadar CTI
4×ModifiedNov 22, 2023 – Aug 27, 2026 · SOCRadar CTI
2×Github ReposDec 8, 2019 – Dec 5, 2023 · SOCRadar CTI
1×CVE appeared in the Cve Trends.Aug 28, 2026 · SOCRadar CTI

References

7 on the record

owncloud.com/security-advisories/webdav-api-authentication-bypass-using-pre-signed-urls/
Vendor Advisory, NIST, MITRE
owncloud.org/security
Product, NIST, MITRE, Vendor Advisory
hunt.io/blog/chinese-speaking-operator-philippine-nuclear-naval-contractor
Third Party Advisory, NIST
www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-49105
US Government Resource, NIST
www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
US Government Resource
www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
US Government Resource
nvd.nist.gov/vuln/detail/CVE-2023-49105
Vendor Advisory

Coverage

8 stories from the feeds we poll

3 more reports on this CVEShowing 5 of 8 · Vendor research and security press coverageUnlock free

Elsewhere on this site

ownCloudevery CVE for this vendor
August 2026what else CISA listed
Auth Bypasssame class
CWE-287other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

Only the 5 indicator(s) reported for this CVE are available; no packet-level or host-forensic artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2023-49105 is ownCloud Improper Authentication Vulnerability, a critical vulnerability affecting ownCloud from ownCloud. The current evidence lists it in CISA KEV, and the exploit status is: Yes: CISA KEV signal present. Public exploit evidence is: 4 public PoC repositories reported; 1 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 9.8 describes technical severity, while EPSS 43% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.