7.5

CVE-2019-9516: Some HTTP/2 implementations are vulnerable to a header leak, potentially leading to a denial of service

Modified
AliasesALPINE-CVE-2019-9516UBUNTU-CVE-2019-9516DEBIAN-CVE-2019-9516
Published 13-08-2019Last modified 04-08-2024

Vulnerability summary

CVE-2019-9516 is a high (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in apache traffic_server. EPSS estimates a 57.46% chance of exploitation in the next 30 days, higher than 99% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.5 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 57% (FIRST, 04-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.0 (CVE.org)
EPSS score
57.46%
0%100%
Critical · +1.20 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 26 · Related 13
DSA-4505-1MGASA-2019-0342MGASA-2020-0372OPENSUSE-SU-2019:2114-1OPENSUSE-SU-2019:2115-1OPENSUSE-SU-2019:2120-1

Timeline

  1. 13-08-2019
    PublishedVulnerability first disclosed.
  2. 04-08-2024
    Last modifiedVulnerability information updated.

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.

CVSS metrics

8 scores · 5 sources · 3 versions

EPSS trend

Probability

57.46%

Chance of exploitation in the next 30 days

Percentile

99%

Versus all other CVEs

30-day change

Increase +1.20 pp

From 56.26% on 05-10-2026

05-10-202604-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Redhat6 products
Synology3 products
Alpine2 products
  • nginx≥ 1.9.5, < 1.16.1-r0 | ≥ 1.9.5, < 1.14.1-r1 | ≥ 1.9.5, < 1.14.1-r2
  • nodejs< 10.16.3-r0
Debian2 products
Apache1 product
  • traffic_server≥ 6.0.0, ≤ 6.2.3 | ≥ 7.0.0, ≤ 7.1.6 | ≥ 8.0.0, ≤ 8.0.3
Apple1 product
Canonical1 product
F51 product
  • nginx≥ 1.9.5, < 1.16.1 | ≥ 1.17.0, ≤ 1.17.2
Fedoraproject1 product
Mcafee1 product
  • web_gateway≥ 7.7.2.0, < 7.7.2.24 | ≥ 7.8.2.0, < 7.8.2.13 | ≥ 8.1.0, < 8.2.0
Nodejs1 product
  • node.js≥ 8.0.0, < 8.16.1 | ≥ 10.0.0, < 10.16.3 | ≥ 12.0.0, < 12.8.1
Opensuse1 product
Oracle1 product
Ubuntu1 product
  • nginx< 1.10.3-0ubuntu0.16.04.4 | < 1.14.0-0ubuntu1.4

14 vendors · 23 products

References

43 links
Show all 43 references