Evidence used
- No CISA KEV confirmation is currently recorded.
- The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
- EPSS is 1.13% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2025
CVE-2025-49826High confidence
Next.js DoS vulnerability via cache poisoning
vercel · next.js
Official source article: GitHub GHSA-67RR-84XM-4C7R ↗. Check the applicable product and release in the original source.
7.5HighCVSS 3.1
Patch only the product branches with a verified fix
Fix availability varies by productHigh technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 44 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:High, unchanged from published severity.unchanged
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict the affected network interface to trusted sources where business-safe.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs vercel next.js and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Remediation availability differs by product scope
Verified remediation exists for at least one product or source, but 44 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
- Red Hat Product Security: 44 affected or under-investigation product states without a fixed product state in the same current advisory
Open-source package ranges1 source-attributed range
These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.
| Ecosystem and package | Affected range | First fixed version | Evidence |
|---|---|---|---|
| npmnext | >= 15.0.4-canary.51, < 15.1.8 | 15.1.8 | GitHub advisory ↗upstream repository advisory · 3 Jul 2025 |
Direct vendor intelligence
1 currentAuthoritative vendor CSAF and VEX advisories
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
CVE-2025-49826 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitynextjs: Next.js denial of service
The vendor explicitly identifies these products as affected by this CVE.
- firefox as a component of Red Hat Enterprise Linux 10
- firefox.src as a component of Red Hat Enterprise Linux 10
- thunderbird as a component of Red Hat Enterprise Linux 10
- thunderbird.src as a component of Red Hat Enterprise Linux 10
- firefox as a component of Red Hat Enterprise Linux 7
- firefox.src as a component of Red Hat Enterprise Linux 7
- firefox as a component of Red Hat Enterprise Linux 8
- firefox.src as a component of Red Hat Enterprise Linux 8
- thunderbird as a component of Red Hat Enterprise Linux 8
- thunderbird.src as a component of Red Hat Enterprise Linux 8
- firefox as a component of Red Hat Enterprise Linux 9
- firefox-x11 as a component of Red Hat Enterprise Linux 9
- Summary
- A denial of service flaw was found in Next.js. In certain situations, this issue may lead to an HTTP 204 response being cached for static pages, which can result in the 204 response being provided to all users trying to access the page.
- Remediation
- Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 44 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Fix availability varies by product01
What, why and how
Next.js is a React framework for building full-stack web applications. From versions 15.0.4-canary.51 to before 15.1.8, a cache poisoning bug leading to a Denial of Service (DoS) condition was found in Next.js. This issue does not impact customers hosted on Vercel. Under certain conditions, this issue may allow a HTTP 204 response to be cached for static pages, leading to the 204 response being served to all users attempting to access the page. This issue has been addressed in version 15.1.8.
What
Next.js is a React framework for building full-stack web applications. From versions 15.0.4-canary.51 to before 15.1.8, a cache poisoning bug leading to a Denial of Service (DoS) condition was found in Next.js. This issue does not impact customers hosted on Vercel. Under certain conditions, this issue may allow a HTTP 204 response to be cached for static pages, leading to the 204 response being served to all users attempting to access the page. This issue has been addressed in version 15.1.8.
Why
The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.
What
Next.js is a React framework for building full-stack web applications. From versions 15.0.4-canary.51 to before 15.1.8, a cache poisoning bug leading to a Denial of Service (DoS) condition was found in Next.js. This issue does not impact customers hosted on Vercel. Under certain conditions, this issue may allow a HTTP 204 response to be cached for static pages, leading to the 204 response being served to all users attempting to access the page. This issue has been addressed in version 15.1.8.
Why
The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- a network path → Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') → disrupt the affected service
- Attack surface
- Network
- Privileges required
- None: unauthenticated exploitation is possible
- User interaction
- None
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Unchanged: impact remains within the vulnerable component's security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-444 ↗
CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling'). The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.- Post-exploitation / living off the land
- No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Fix availability varies by product
- Affected
- firefox as a component of Red Hat Enterprise Linux 10
- firefox.src as a component of Red Hat Enterprise Linux 10
- thunderbird as a component of Red Hat Enterprise Linux 10
- thunderbird.src as a component of Red Hat Enterprise Linux 10
- firefox as a component of Red Hat Enterprise Linux 7
- firefox.src as a component of Red Hat Enterprise Linux 7
- firefox as a component of Red Hat Enterprise Linux 8
- firefox.src as a component of Red Hat Enterprise Linux 8
- thunderbird as a component of Red Hat Enterprise Linux 8
- thunderbird.src as a component of Red Hat Enterprise Linux 8
- firefox as a component of Red Hat Enterprise Linux 9
- firefox-x11 as a component of Red Hat Enterprise Linux 9
- firefox.src as a component of Red Hat Enterprise Linux 9
- thunderbird as a component of Red Hat Enterprise Linux 9
- thunderbird.src as a component of Red Hat Enterprise Linux 9
- rhelai1/docling-serve-rhel9 as a component of Red Hat Enterprise Linux AI (RHEL AI)
- rhelai1/granite-3.1-8b-lab-v1 as a component of Red Hat Enterprise Linux AI (RHEL AI)
- rhelai1/granite-3.1-8b-starter-v1 as a component of Red Hat Enterprise Linux AI (RHEL AI)
- rhelai1/granite-7b-redhat-lab as a component of Red Hat Enterprise Linux AI (RHEL AI)
- rhelai1/granite-7b-starter as a component of Red Hat Enterprise Linux AI (RHEL AI)
- rhelai1/granite-8b-code-base as a component of Red Hat Enterprise Linux AI (RHEL AI)
- rhelai1/granite-8b-code-instruct as a component of Red Hat Enterprise Linux AI (RHEL AI)
- rhelai1/granite-8b-lab-v1 as a component of Red Hat Enterprise Linux AI (RHEL AI)
- rhelai1/granite-8b-lab-v2-preview as a component of Red Hat Enterprise Linux AI (RHEL AI)
- rhelai1/granite-8b-starter-v1 as a component of Red Hat Enterprise Linux AI (RHEL AI)
- rhelai1/knowledge-adapter-v3 as a component of Red Hat Enterprise Linux AI (RHEL AI)
- rhelai1/mixtral-8x7b-instruct-v0-1 as a component of Red Hat Enterprise Linux AI (RHEL AI)
- rhelai1/modelcar-docling-layout as a component of Red Hat Enterprise Linux AI (RHEL AI)
- rhelai1/modelcar-docling-tableformer as a component of Red Hat Enterprise Linux AI (RHEL AI)
- rhelai1/modelcar-granite-3-1-8b-lab-v1 as a component of Red Hat Enterprise Linux AI (RHEL AI)
- and 14 more
- Fixed
- 15.1.8.
- Action
- Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
- Workaround
- Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
04
Evidence and provenance
Published 3 Jul 2025 · Last source change 8 Jul 2025, 14:33 UTC · CWE-444 · Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-14
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2025-19910
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.