CVSS 4.0
8.7 highCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NCVE-2026-123487
High (8.7) in parse-community parse-server. EPSS 0.4% estimated probability of exploitation activity in the next 30 days.
On this page
Parse Server before 8.6.115 and 9.0.0 before 9.10.7-alpha.1 validates user email address format with a regular expression whose run time grows quadratically with input length and that is applied without a length limit. An unauthenticated attacker who knows the application ID can send a sign-up request, or a logged-in user can update their own email, with a long crafted email address to block the Node.js event loop and deny service to all clients.
Severity
CVSS 3.1
7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- EPSS
- 0.4% estimated probability of exploitation activity in the next 30 days; 33rd percentile. Scored 2026-11-10. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: yes · Technical impact: partial, assessed 2026-11-06. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-1333 Inefficient Regular Expression Complexity
- Published
- Modified
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
Ask an AI about this CVE
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Explain CVE-2026-123487 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-123487?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-123487?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-123487 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| parse-community parse-server | from 9.0.0 before 9.10.7-alpha.1 |
| parse-community parse-server | before 8.6.115 |
Attack patterns (CAPEC)
- CAPEC-492 Regular Expression Exponential Blowup
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.