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 0.62% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-71418High confidence
Suricata doh2: crafted HTTP/2 DATA frames can cause quadratic CPU consumption
OISF · suricata
Official source article: GitHub GHSA-XJGQ-3QW4-JP5F ↗. 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 1 structured product or package state 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 OISF suricata 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 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
- Debian Security Tracker: 1 affected package state with no published fix
Distribution package intelligence
4 package statesRelease-specific package status
Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
Package result overrides the generic status
BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 1 affected package state shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
| Distribution release | Source package | Vendor state | Fixed version | Evidence |
|---|---|---|---|---|
| Debian trixietrixie · source | suricata | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 4 Oct 2026 |
| Debian forkyforky · source | suricata | Vendor fix publishedDebian records a fixed source-package version for this release. | 1:8.0.6-1 | Debian Security Tracker ↗Source updated 4 Oct 2026 |
| Debian sidsid · source | suricata | Vendor fix publishedDebian records a fixed source-package version for this release. | 1:8.0.6-1 | Debian Security Tracker ↗Source updated 4 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | suricata | Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing. | Not published in this feed | Canonical Ubuntu Security ↗Source updated 2 Oct 2026 |
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-2026-71418 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitysuricata: Suricata: Denial of Service via crafted HTTP/2 DATA frames
The vendor explicitly states that these products are not affected by this CVE.
- All currently supported Red Hat products
- Summary
- A flaw was found in Suricata, a network Intrusion Detection System, Intrusion Prevention System, and Network Security Monitoring engine. Its DNS-over-HTTP/2 processing incorrectly retains previously processed HTTP/2 DATA frame contents. A remote attacker can exploit this by sending multiple crafted HTTP/2 DATA frames with the EndOfStream flag set. This causes the internal buffer to grow and reprocess prior contents, leading to quadratic CPU consumption. This can result in degraded packet processing, loss of monitoring visibility, or a denial of service (DoS) condition.
- Remediation
- No remediation text is recorded.
High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 1 structured product or package state remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Fix availability varies by product01
What, why and how
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. From 8.0.0 until 8.0.6, DNS-over-HTTP/2 processing in rust/src/http2/http2.rs retains previously processed HTTP/2 DATA frame contents instead of clearing the internal buffer. Multiple DATA frames with the EndOfStream flag set can grow the buffer to its 65 KiB limit while causing all prior contents to be processed again, producing quadratic CPU complexity, degraded packet processing, loss of monitoring visibility, or denial of service. This issue is fixed in version 8.0.6.
What
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. From 8.0.0 until 8.0.6, DNS-over-HTTP/2 processing in rust/src/http2/http2.rs retains previously processed HTTP/2 DATA frame contents instead of clearing the internal buffer. Multiple DATA frames with the EndOfStream flag set can grow the buffer to its 65 KiB limit while causing all prior contents to be processed again, producing quadratic CPU complexity, degraded packet processing, loss of monitoring visibility, or denial of service. This issue is fixed in version 8.0.6.
Why
An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.
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
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. From 8.0.0 until 8.0.6, DNS-over-HTTP/2 processing in rust/src/http2/http2.rs retains previously processed HTTP/2 DATA frame contents instead of clearing the internal buffer. Multiple DATA frames with the EndOfStream flag set can grow the buffer to its 65 KiB limit while causing all prior contents to be processed again, producing quadratic CPU complexity, degraded packet processing, loss of monitoring visibility, or denial of service. This issue is fixed in version 8.0.6.
Why
An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.
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 → Inefficient Algorithmic Complexity → 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-407 ↗
CWE-407: Inefficient Algorithmic Complexity. An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.
- 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
- suricata: 8.0.0, < 8.0.6
- Fixed
- 8.0.6.
- 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
- A mitigation or workaround reference is available from the source linked below; validate it against the affected product and version.
Official vendor articles2 stored documents
Linked articles are downloaded and versioned as source evidence. A CVE mention or approved update relationship does not, by itself, verify a fix for every product branch.
- Release 8.0.6 · OISF/suricata · GitHub →Original publisher ↗Searchable text snapshot · Captured 28 Sep 2026OISF / suricata Public Notifications You must be signed in to change notification settings Fork 1.8k Star 6.7k Code Pull requests 105 Actions Security and quality 86 Insights Additional navigation options Code Pull requests Actions Security and quality Insights 8.0.6 Compare Choose a tag to compare Sorry
- doh2: crafted HTTP/2 DATA frames can cause quadratic CPU consumption · Advisory · OISF/suricata · GitHub →Original publisher ↗Searchable text snapshot · Captured 28 Sep 2026OISF / suricata Public Notifications You must be signed in to change notification settings Fork 1.8k Star 6.7k Code Pull requests 105 Actions Security and quality 86 Insights Additional navigation options Code Pull requests Actions Security and quality Insights doh2: crafted HTTP/2 DATA frames can cause q
04
Evidence and provenance
Published 18 Sept 2026 · Last source change 21 Sept 2026, 20:47 UTC · CWE-407 · Inefficient Algorithmic Complexity
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-09-19
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-83397
Product sourceCNA
Remediation sourceCVE/CNA references
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
- Vendor guidanceAuthoritative vendor guidance changed: added mitigation: github.com/GHSA-xjgq-3qw4-jp5f; added patch: github.com/1731805967edf5d31448db2ae43cf72c6cf46c11; removed remediation: github.com/GHSA-xjgq-3qw4-jp5f; 2 further additions.security-advisories@github.com ↗
- Before
- remediation: github.com/GHSA-xjgq-3qw4-jp5f
- After
- mitigation: github.com/GHSA-xjgq-3qw4-jp5f · patch: github.com/1731805967edf5d31448db2ae43cf72c6cf46c11 · patch: github.com/26c26dea84f00de95151a0e16d21c1fcafac9648 · 1 more references
- ENISA EUVD mappingEUVD-2026-83397 was added to the official ENISA EUVD mapping for this CVE.ENISA EUVD ↗
- Before
- not recorded
- After
- {"euvdId":"EUVD-2026-83397"}
- Catalogue recordCVE added to the BlackTree catalogue.CNA ↗
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.