What is CVE-2026-49952?

CVE-2026-49952 is Discuz! X5.0 Authentication Bypass via dbbak.php Encryption Oracle. The supplied enrichment data classifies it as Auth Bypass mapped to CWE-323 CWE-323.

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?

Exploitation is reported, but no independent confirmation is available in the sources we have. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

No. CVE-2026-49952 is not listed in CISA KEV in the supplied enrichment data. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Is there a public exploit?

3 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-2026-49952 using CVSS 9.1, EPSS 5%, 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. Prioritize based on EPSS, PoC availability, and external exposure. 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.

criticalAuth Bypasspublic exploit

CVE-2026-49952

CVE-2026-49952 — Discuz! X5.0 Authentication Bypass via dbbak.php Encryption Oracle

Discuz! X5.0 releases 20260320 through 20260501 contains an authentication bypass vulnerability that allows unauthenticated remote attackers to gain unauthorized access to database backup and restore functionality by exploiting a shared cryptographic key between UCenter integration and the database backup API exposed by dbbak.php. Attackers can inject a crafted payload through the username parameter during login to abuse the encryption oracle in logging_ctl::logging_more(), obtain a legitimately signed token, and use it to bypass authorization for database export and import operations, with the additional ability to trigger a race condition to impersonate arbitrary users.

Published Jun 15, 2026Updated Jun 17, 2026Sources: NVD, Discuz! (CNA), Exploit-DB, SOCRadar CTI

Triage

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

Exploitation

Reported

not confirmed by CISA

EPSS

ahead of 91% of scored CVEs

Affects

Discuz!

Discuz! X5.0

CVSS base

9.1

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

PoC

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 Discuz! X5.0 to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

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.
Prioritize based on EPSS, PoC availability, and external exposure.
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
Discuz!	Discuz! X5.0	20260320 to <= 20260501	Vulnerable

Attack characteristics

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

Availability

None

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
9.1	CVSS 3.1	critical	3.9	5.2	VulnCheck (CNA), Discuz! (CNA)
9.3	CVSS 4.0	critical	—	—	Discuz! (CNA)

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

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-323 · Reusing a Nonce, Key Pair in Encryption

Bypass Protection Mechanism
Gain Privileges or Assume Identity

Mitigation: Refuse to reuse nonce values.

Weakness & attack patterns

CWE-323

Inferred from the weakness class — not observed against this CVE.

CAPEC-115 · Authentication BypassCAPEC-94 · Adversary in the Middle

Public exploit

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

Repositories

1 of the 1 sampled are weaponized

Exploit entries

Exploit-DB and CTI exploit indexes

Detection

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

Prioritize edge telemetry for network-reachable Discuz! X5.0.
Monitor for scanner or exploit-pattern traffic after 3 public PoC repositories were reported.

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

Timeline

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

2026
Cve is exploited Discuz! X5.0 - Authentication Bypass
Jul 8, 2026 · SOCRadar CTI
Added · webapps entry: Discuz! X5.0 - Authentication Bypass
Jul 7, 2026 · Exploit-DB
Added · CVSS 3.1 9.1 (AV:N)
Jun 17, 2026 · NVD
Initial · CVE published
Jun 15, 2026 · NVD

Source activity

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

2×CVE modified by MITRE: CVSS metrics updated.Jun 15, 2026 – Jun 16, 2026 · SOCRadar CTI
1×SVRS is calculatedJun 24, 2026 · SOCRadar CTI
1×Github_Repos · Github repository created, passwa11/CVE-2026-49952Jun 17, 2026 · SOCRadar CTI

References

6 on the record

gitee.com/Discuz/DiscuzX/commit/9962dad52c4c6999dabaf91ecd70377c680ff3c6
Vendor Advisory, NIST
karmainsecurity.com/KIS-2026-09
Vendor Advisory, NIST, GITHUB
karmainsecurity.com/chaining-bugs-in-discuz-from-race-condition-to-rce
Vendor Advisory, NIST, GITHUB
www.vulncheck.com/advisories/discuz-x5-0-authentication-bypass-via-dbbak-php-encryption-oracle
Vendor Advisory, NIST
seclists.org/fulldisclosure/2026/Jun/3
Vendor Advisory, NIST, GITHUB
www.exploit-db.com/exploits/52621
Vendor Advisory

Coverage

1 story from the feeds we poll

CVE-2026-49952
vuldb.com · Jun 16, 2026

Elsewhere on this site

Discuz!every CVE for this vendor
Auth Bypasssame class
CWE-323other 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.

No confirmed IOCs, IP addresses, domains, file hashes, or malware 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-2026-49952 is Discuz! X5.0 Authentication Bypass via dbbak.php Encryption Oracle, a critical vulnerability affecting Discuz! X5.0 from Discuz!. The current evidence does not list it in CISA KEV, and the exploit status is: Exploitation is reported, but no independent confirmation is available in the sources we have. Public exploit evidence is: 3 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 9.1 describes technical severity, while EPSS 5% 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.