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CVE-2019-9516
Some HTTP/2 implementations are vulnerable to a header leak, potentially leading to a denial of service
- 7.5HighCVSS base score
- 57.5%Exploitation in 30 daysEPSS · top 0.9% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
Some HTTP/2 implementations are vulnerable to a header leak, potentially leading to a denial of service. The attacker sends a stream of headers with a 0-length header name and 0-length header value, optionally Huffman encoded into 1-byte or greater headers. Some implementations allocate memory for these headers and keep the allocation alive until the session dies. This can consume excess memory.
Timeline
ID reserved
By certcc
- 6 months later
· 6 months later
Published
- 5 years later
· 5 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| certccCNA (assigner) | 3.0 | High7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Modified | 3.1 | Medium6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 57.5% · top 0.9% of all CVEs (11 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
n/a
- affected n/a
References
References37
- VU#605641 (opens in a new tab)third-party-advisoryx_refsource_CERT-VNx_transferred
- https://github.com/Netflix/security-bulletins/blob/master/advisories/third-party/2019-002.md (opens in a new tab)x_refsource_MISCx_transferred
- 20190814 APPLE-SA-2019-08-13-5 SwiftNIO HTTP/2 1.5.0 (opens in a new tab)mailing-listx_refsource_BUGTRAQx_transferred
- USN-4099-1 (opens in a new tab)vendor-advisoryx_refsource_UBUNTUx_transferred
- 20190816 APPLE-SA-2019-08-13-5 SwiftNIO HTTP/2 1.5.0 (opens in a new tab)mailing-listx_refsource_FULLDISCx_transferred
- https://www.synology.com/security/advisory/Synology_SA_19_33 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://support.f5.com/csp/article/K02591030 (opens in a new tab)x_refsource_CONFIRMx_transferred
- FEDORA-2019-befd924cfe (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- 20190822 [SECURITY] [DSA 4505-1] nginx security update (opens in a new tab)mailing-listx_refsource_BUGTRAQx_transferred
- DSA-4505 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
- https://security.netapp.com/advisory/ntap-20190823-0002/ (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://security.netapp.com/advisory/ntap-20190823-0005/ (opens in a new tab)x_refsource_CONFIRMx_transferred
- FEDORA-2019-5a6a7bc12c (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- FEDORA-2019-6a2980de56 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- FEDORA-2019-4427fd65be (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- FEDORA-2019-63ba15cc83 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- FEDORA-2019-7a0b45fdc4 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- openSUSE-SU-2019:2120 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
- openSUSE-SU-2019:2114 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
- openSUSE-SU-2019:2115 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
- https://kc.mcafee.com/corporate/index?page=content&id=SB10296 (opens in a new tab)x_refsource_CONFIRMx_transferred
- RHSA-2019:2745 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- RHSA-2019:2746 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- RHSA-2019:2775 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- RHSA-2019:2799 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- RHSA-2019:2925 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- RHSA-2019:2939 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- RHSA-2019:2946 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- RHSA-2019:2950 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- RHSA-2019:2955 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- RHSA-2019:2966 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- openSUSE-SU-2019:2264 (opens in a new tab)vendor-advisoryx_refsource_SUSEx_transferred
- https://support.f5.com/csp/article/K02591030?utm_source=f5support&%3Butm_medium=RSS (opens in a new tab)x_refsource_CONFIRMx_transferred
- RHSA-2019:3933 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- RHSA-2019:3935 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- RHSA-2019:3932 (opens in a new tab)vendor-advisoryx_refsource_REDHATx_transferred
- FEDORA-2021-d5b2c18fe6 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2019-18888 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://cveledger.app/cve/CVE-2019-9516)Record last updated .