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CVE-2013-3656· NVD / CVE Program· CNA jpcert

Cybozu Office 9.1.0 and earlier does not properly manage sessions, which allows remote attackers to bypass authentication by leveraging know

Cybozu Office 9.1.0 and earlier does not properly manage sessions, which allows remote attackers to bypass authentication by leveraging knowledge of a login URL.

MediumCVSS 5.8 · v2.0—No exploit No fix recorded
Published
Jul 19, 2013
Updated
Jun 16, 2026
EPSS
2.0% · 80th percentile
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JSON

Action score

24

Monitor

Low priority for now.

CVSS
23 / 40 · 5.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 2.0%

Affected systems

VendorProduct
cybozucybozu office

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • cybozu cybozu officeup to 9.1.0 inclusive

Same product

cybozu: all records

Other highest-scoring records for the same primary product.

  • CVE-2013-3269Cross-site request forgery (CSRF) vulnerability in Cybozu Office before 8.1.6 and 9.x before 9.3.0 allows remote attackers to hijack the aut
    27Monitor
  • CVE-2013-2305Cross-site request forgery (CSRF) vulnerability in Cybozu Office before 8.1.6 and 9.x before 9.3.0, Cybozu Dezie before 8.0.7, and Cybozu Ma
    27Monitor
  • CVE-2010-2029Cybozu Office 7 Ktai and Dotsales do not properly restrict access to the login page, which allows remote attackers to bypass authentication
    23Monitor
  • CVE-2006-4492Unspecified vulnerability in Cybozu Office 6.5 Build 1.2 for Windows allows remote attackers to obtain sensitive information, including user
    20Monitor
  • CVE-2006-4490Multiple directory traversal vulnerabilities in Cybozu Office before 6.6 Build 1.3 and Share 360 before 2.5 Build 0.3 allow remote authentic
    17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

    If successful

    Confidentiality
    P · data can be read
    Integrity
    P · data or configuration can be modified
    Availability
    none
    Attack complexity
    M
    Confidentiality impact
    P
    Integrity impact
    P
    Availability impact
    None

    Weakness class (CWE)

    CWE-287 · Improper Authentication

    CVSS vector

    AV:N/AC:M/Au:N/C:P/I:P/A:N

    nvd-primary

    Root cause

    Authentication is added route by route instead of being enforced in one place. When a route added later bypasses the shared middleware, the session check never runs for it.

    The bug in code

    The whole CWE-287 class

    A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

    Vulnerable

    ts
    app.use("/admin", requireSession, adminRouter);
// Route added later skips the middlewareapp.post("/admin-api/config", updateConfig);

    Fixed

    ts
    const admin = express.Router();admin.use(requireSession, requireRole("admin"));
admin.post("/config", updateConfig);app.use("/admin", admin);

    Attack context

    MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

    Noroxi analysis

    No Noroxi analysis for this record yet

    We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

    We use this product, ask for help

    Change log

    No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

    References

    Vendor advisories and official records. Exploit/PoC links are deliberately left out.

    All records