CVE-2018-0732: Client DoS due to large DH parameter
Vulnerability summary
CVE-2018-0732 is a high (CVSS 7.5) Key Management Errors vulnerability in canonical ubuntu_linux. EPSS estimates a 47.01% chance of exploitation in the next 30 days, higher than 98.8% of scored vulnerabilities.
Severe, CVSS 7.5 (NVD); no exploitation reported by the 5 checked sources; EPSS 47% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 22 · Related 13Timeline
- 12-06-2018PublishedVulnerability first disclosed.
- 08-10-2026Last modifiedVulnerability information updated.
Description
During key agreement in a TLS handshake using a DH(E) based ciphersuite a malicious server can send a very large prime value to the client. This will cause the client to spend an unreasonably long period of time generating a key for this prime resulting in a hang until the client has finished. This could be exploited in a Denial Of Service attack. Fixed in OpenSSL 1.1.0i-dev (Affected 1.1.0-1.1.0h). Fixed in OpenSSL 1.0.2p-dev (Affected 1.0.2-1.0.2o).
CVSS metrics
6 scores · 4 sources · 3 versions- OSV · AlpineEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
47.01%
Chance of exploitation in the next 30 days
Percentile
99%
Versus all other CVEs
30-day change
Decrease -1.82 pp
From 48.83% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Suse21 products
- openssl-1_0_0&distro=SUSE Linux Enterprise Module for Legacy 15< 1.0.2n-3.3.1
- openssl-1_1&distro=SUSE Linux Enterprise Module for Basesystem 15< 1.1.0h-4.3.1 | < 1.1.0i-4.9.2
- openssl&distro=SUSE Enterprise Storage 4< 1.0.2j-60.30.1
- openssl&distro=SUSE Linux Enterprise Desktop 12 SP3< 1.0.2j-60.30.1
- openssl&distro=SUSE Linux Enterprise Module for Basesystem 15< 1.1.0i-3.3.1
Alpine2 products
- libressl< 2.7.4-r0 | < 2.6.5-r0
- openssl≥ 1.0.2, < 1.0.2o-r1
Debian2 products
- openssl< 1.1.1-1
- debian_linuxEOL8.0
Ubuntu2 products
- openssl< 1.0.1f-1ubuntu2.26 | < 1.0.2g-1ubuntu4.13 | < 1.1.0g-2ubuntu4.1
- openssl1.0< 1.0.2n-1ubuntu5.1
Canonical1 product
- ubuntu_linuxEOL12.04 | 14.04 | 16.04 | 17.10 | 18.04
Nodejs1 product
- node.js≥ 6.0.0, < 6.8.1 | ≥ 6.9.0, < 6.14.4 | ≥ 8.0.0, < 8.8.1 | ≥ 8.9.0, < 8.11.4 | ≥ 10.0.0, < 10.9.0
Openssl1 product
- opensslFixed in OpenSSL 1.1.0i-dev (Affected 1.1.0-1.1.0h) | Fixed in OpenSSL 1.0.2p-dev (Affected 1.0.2-1.0.2o) | ≥ 1.0.2, ≤ 1.0.2o | ≥ 1.1.0, ≤ 1.1.0h
7 vendors · 30 products
References
55 links
lists.debian.org/debian-lts-announce/2018/07/msg00043.htmlMailing ListX Refsource MLISTThird Party Advisory
Show all 55 references
- www.oracle.com/technetwork/security-advisory/cpuoct2018-4428296.htmlX Refsource CONFIRMPatchThird Party Advisory
- www.oracle.com/technetwork/security-advisory/cpujan2019-5072801.htmlX Refsource CONFIRMPatchThird Party Advisory
- www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.htmlX Refsource MISCPatchThird Party Advisory
- www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.htmlX Refsource MISCPatchThird Party Advisory
- www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.htmlX Refsource MISCPatchThird Party Advisory