Zammad: Arbitrary File Deletion via Unvalidated Session Identifier in Long Polling Controller
Zammad is a web based open source helpdesk/customer support system. In 7.0.2 and 7.1.0, zammad's session management for websocket and long-polling connections is susceptible to a path traversal attack. Session identifiers supplied by the client are insufficiently validated before being used to construct internal file paths. When the file-based session store is active (the default configuration), an authenticated attacker can manipulate the session identifier to reference locations outside the intended storage directory, leading to the deletion of arbitrary files and directories on the server. Exploitation requires only a low-privilege authenticated session and a single crafted request. Instances configured to use the Redis-based session store are not affected. This issue is fixed in versions 7.0.3 and 7.1.1.
- Published
- Sep 25, 2026
- Updated
- Sep 28, 2026
- EPSS
- 0.4% · 27th percentile
- CWE
- CWE-22
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
35
Monitor
Low priority for now.
- CVSS
- 35 / 40 · 8.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.4%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 8.8
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; 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 helpAffected systems
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
zammad zammad
- = 7.0.2, = 7.1.0affected
Same product
zammad: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-102490Undisclosed LPE in Zammad v1.5.0 to v7.1.0-alphaKEV67This week
- CVE-2026-102489Undisclosed RCE in Zammad v6.3 and higherKEV67This week
- CVE-2021-42090An issue was discovered in Zammad before 4.1.1.40Plan
- CVE-2021-42094An issue was discovered in Zammad before 4.1.1.40Plan
- CVE-2022-48021A vulnerability in Zammad v5.3.0 allows attackers to execute arbitrary code or escalate privileges via a crafted message sent to the server.39Monitor
- CVE-2022-35490Zammad 5.2.0 is vulnerable to privilege escalation.39Monitor
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.
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.
Credits
All researchersFinders, 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.
- CVE-2026-630060 days apartZammad: HTML sanitizer API path allowlist bypass via interior path traversal in img src/srcset21Monitor
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
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
nvd-secondary
Root cause
A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.
The bug in code
The whole CWE-22 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
const file = path.join(ROOT, req.query.name);res.sendFile(file);Fixed
const file = path.resolve(ROOT, req.query.name);if (!file.startsWith(ROOT + path.sep)) { return res.sendStatus(400);}res.sendFile(file);Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Path TraversalCAPEC-126likelihood: High · Very High
- Using Slashes and URL Encoding Combined to Bypass Validation LogicCAPEC-64likelihood: High · High
- Manipulating Web Input to File System CallsCAPEC-76likelihood: High · Very High
- Using Escaped Slashes in Alternate EncodingCAPEC-78likelihood: High · High
- Using Slashes in Alternate EncodingCAPEC-79likelihood: High · High
ATT&CK techniques
—
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- github.com/zammad/zammad/commit/cf3425712e8fae1bd40fa5814a49dc318dc84006
- github.com/zammad/zammad/commit/f78ef2434fd8aad6c2fb8a702788f6e3f33565f6
- github.com/zammad/zammad/security/advisories/GHSA-xp9w-hhf3-vfxx
Vendor advisories and official records. Exploit/PoC links are deliberately left out.