# CVE-2018-3639: Information disclosure in Multiple > Local attackers can exploit Speculative Store Bypass to disclose sensitive memory information via side-channel analysis on affected systems. - **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 22 May 2018 - **Updated:** 29 May 2026 - **Also known as:** ALPINE-CVE-2018-3639, CLEANSTART-2026-JY98800, DEBIAN-CVE-2018-3639, DSA-4210-1, MGASA-2018-0262, MGASA-2018-0298, RHSA-2018:1629, RHSA-2018:1630, RHSA-2018:1632, RHSA-2018:1633, RHSA-2018:1635, RHSA-2018:1636, RHSA-2018:1637, RHSA-2018:1638, RHSA-2018:1639, RHSA-2018:1640, RHSA-2018:1641, RHSA-2018:1642, RHSA-2018:1647, RHSA-2018:1648, RHSA-2018:1649, RHSA-2018:1650, RHSA-2018:1651, RHSA-2018:1652, RHSA-2018:1653, RHSA-2018:1654, RHSA-2018:1655, RHSA-2018:1656, RHSA-2018:1657, RHSA-2018:1658, RHSA-2018:1659, RHSA-2018:1660, RHSA-2018:1661, RHSA-2018:1662, RHSA-2018:1663, RHSA-2018:1664, RHSA-2018:1665, RHSA-2018:1666, RHSA-2018:1667, RHSA-2018:1668, RHSA-2018:1669, RHSA-2018:1674, RHSA-2018:1675, RHSA-2018:1676, RHSA-2018:1686, RHSA-2018:1688, RHSA-2018:1689, RHSA-2018:1690, RHSA-2018:1696, RHSA-2018:1738, RHSA-2018:1826, RHSA-2018:1997, RHSA-2018:2001, RHSA-2018:2006, RHSA-2018:2060, RHSA-2018:2161, RHSA-2018:2171, RHSA-2018:2216, RHSA-2018:2228, RHSA-2018:2246, RHSA-2018:2250, RHSA-2018:2258, RHSA-2018:2289, RHSA-2018:2309, RHSA-2018:2328, RHSA-2018:2363, RHSA-2018:2364, RHSA-2018:3396, RHSA-2018:3397, RHSA-2018:3398, RHSA-2018:3399, RHSA-2018:3400, RHSA-2018:3401, RHSA-2018:3402, RHSA-2018:3407, RHSA-2018:3423, RHSA-2018:3424, RHSA-2018:3425, RHSA-2019:0148, RHSA-2019:1046, SUSE-SU-2018:1362-1, SUSE-SU-2018:1362-2, SUSE-SU-2018:1377-1, SUSE-SU-2018:1377-2, SUSE-SU-2018:1378-1, SUSE-SU-2018:1389-1, SUSE-SU-2018:1452-1, SUSE-SU-2018:1475-1, SUSE-SU-2018:1479-1, SUSE-SU-2018:1582-1, SUSE-SU-2018:1614-1, SUSE-SU-2018:1614-2, SUSE-SU-2018:2304-1, UBUNTU-CVE-2018-3639, USN-3651-1, USN-3652-1, USN-3679-1 ## What is CVE-2018-3639? CVE-2018-3639 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 22 May 2018. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description Systems with microprocessors utilizing speculative execution and speculative execution of memory reads before the addresses of all prior memory writes are known may allow unauthorized disclosure of information to an attacker with local user access via a side-channel analysis, aka Speculative Store Bypass (SSB), Variant 4. Weakness: CWE-203 (Observable Discrepancy) ## Which versions are affected by CVE-2018-3639? It affects 282 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `java-1.7.0-openjdk` | Red Hat:enterprise_linux:6::client | All versions | 1:1.7.0.181-2.6.14.8.el6_9 | | `java-1.7.0-openjdk-debuginfo` | Red Hat:enterprise_linux:6::client | All versions | 1:1.7.0.181-2.6.14.8.el6_9 | | `java-1.7.0-openjdk-demo` | Red Hat:enterprise_linux:6::client | All versions | 1:1.7.0.181-2.6.14.8.el6_9 | | `java-1.7.0-openjdk-devel` | Red Hat:enterprise_linux:6::client | All versions | 1:1.7.0.181-2.6.14.8.el6_9 | | `java-1.7.0-openjdk-javadoc` | Red Hat:enterprise_linux:6::client | All versions | 1:1.7.0.181-2.6.14.8.el6_9 | | `java-1.7.0-openjdk-src` | Red Hat:enterprise_linux:6::client | All versions | 1:1.7.0.181-2.6.14.8.el6_9 | | `java-1.8.0-openjdk` | Red Hat:enterprise_linux:6::client | All versions | 1:1.8.0.171-8.b10.el6_9 | | `java-1.8.0-openjdk-debug` | Red Hat:enterprise_linux:6::client | All versions | 1:1.8.0.171-8.b10.el6_9 | | `java-1.8.0-openjdk-debuginfo` | Red Hat:enterprise_linux:6::client | All versions | 1:1.8.0.171-8.b10.el6_9 | | `java-1.8.0-openjdk-demo` | Red Hat:enterprise_linux:6::client | All versions | 1:1.8.0.171-8.b10.el6_9 | | `java-1.8.0-openjdk-demo-debug` | Red Hat:enterprise_linux:6::client | All versions | 1:1.8.0.171-8.b10.el6_9 | | `java-1.8.0-openjdk-devel` | Red Hat:enterprise_linux:6::client | All versions | 1:1.8.0.171-8.b10.el6_9 | | `java-1.8.0-openjdk-devel-debug` | Red Hat:enterprise_linux:6::client | All versions | 1:1.8.0.171-8.b10.el6_9 | | `java-1.8.0-openjdk-headless` | Red Hat:enterprise_linux:6::client | All versions | 1:1.8.0.171-8.b10.el6_9 | | `java-1.8.0-openjdk-headless-debug` | Red Hat:enterprise_linux:6::client | All versions | 1:1.8.0.171-8.b10.el6_9 | | `java-1.8.0-openjdk-javadoc` | Red Hat:enterprise_linux:6::client | All versions | 1:1.8.0.171-8.b10.el6_9 | | `java-1.8.0-openjdk-javadoc-debug` | Red Hat:enterprise_linux:6::client | All versions | 1:1.8.0.171-8.b10.el6_9 | | `java-1.8.0-openjdk-src` | Red Hat:enterprise_linux:6::client | All versions | 1:1.8.0.171-8.b10.el6_9 | | `java-1.8.0-openjdk-src-debug` | Red Hat:enterprise_linux:6::client | All versions | 1:1.8.0.171-8.b10.el6_9 | | `kernel` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | | `kernel-abi-whitelists` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | | `kernel-debug` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | | `kernel-debug-debuginfo` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | | `kernel-debug-devel` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | | `kernel-debuginfo` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | | `kernel-debuginfo-common-i686` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | | `kernel-debuginfo-common-x86_64` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | | `kernel-devel` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | | `kernel-doc` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | | `kernel-firmware` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | | `kernel-headers` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | | `libvirt` | Red Hat:enterprise_linux:6::client | All versions | 0:0.10.2-62.el6_9.2 | | `libvirt-client` | Red Hat:enterprise_linux:6::client | All versions | 0:0.10.2-62.el6_9.2 | | `libvirt-debuginfo` | Red Hat:enterprise_linux:6::client | All versions | 0:0.10.2-62.el6_9.2 | | `libvirt-devel` | Red Hat:enterprise_linux:6::client | All versions | 0:0.10.2-62.el6_9.2 | | `libvirt-lock-sanlock` | Red Hat:enterprise_linux:6::client | All versions | 0:0.10.2-62.el6_9.2 | | `libvirt-python` | Red Hat:enterprise_linux:6::client | All versions | 0:0.10.2-62.el6_9.2 | | `perf` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | | `perf-debuginfo` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | | `python-perf` | Red Hat:enterprise_linux:6::client | All versions | 0:2.6.32-696.30.1.el6 | Products: Arm Cortex-A, Canonical Ubuntu Linux, Debian Debian Linux, Intel Atom C, Intel Atom E, Intel Atom X5-E3930, Intel Atom X5-E3940, Intel Atom X7-E3950, Intel Atom Z, Intel Celeron J, Intel Celeron N, Intel Core I3, Intel Core I5, Intel Core I7, Intel Core M, Intel Pentium, Intel Pentium J, Intel Pentium Silver, Intel Xeon E-1105c, Intel Xeon E3 and 262 more. ## How do I fix CVE-2018-3639? Apply the vendor's patch. ## Is CVE-2018-3639 being exploited? It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-3639 exists. Public exploit code: - Speculative Store Bypass (CVE-2018-3639) proof of concept for Linux (github_poc): https://github.com/mmxsrup/CVE-2018-3639 - Tools to exercise the Linux kernel mitigation for CVE-2018-3639 (aka Variant 4) using the Speculative Store Bypass Disable (SSBD) feature of x86 processors (github_poc): https://github.com/tyhicks/ssbd-tools - spectre v4 : Speculative Store Bypass (CVE-2018-3639) proof of concept for Linux (github_poc): https://github.com/Shuiliusheng/CVE-2018-3639-specter-v4- - AMD / ARM / Intel - Speculative Execution Variant 4 Speculative Store Bypass (exploitdb) - https://github.com/malindarathnayake/Intel-CVE-2018-3639-Mitigation_RegistryUpdate (github_poc): https://github.com/malindarathnayake/Intel-CVE-2018-3639-Mitigation_RegistryUpdate ## Other vulnerabilities in Canonical Ubuntu Linux - [CVE-2018-3693](https://insights.sbomify.com/CVE-2018-3693/): Information disclosure in Most Modern Operating Systems (medium 5.6) - [CVE-2018-3640](https://insights.sbomify.com/CVE-2018-3640/): Information disclosure in Multiple (medium 5.6) - [CVE-2018-9056](https://insights.sbomify.com/CVE-2018-9056/): Information disclosure in n/a (medium 5.6) - [CVE-2017-5715](https://insights.sbomify.com/CVE-2017-5715/): Information disclosure in Microprocessors with Speculative Execution (medium 5.6) - [CVE-2017-5754](https://insights.sbomify.com/CVE-2017-5754/): Information disclosure in Most Modern Operating Systems (medium 5.6) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2018-3639 and fix it if it is affected. What it is: CVE-2018-3639 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 22 May 2018. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-3639 exists. Affected product: Canonical Ubuntu Linux. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2018-3639/ (Markdown: https://insights.sbomify.com/CVE-2018-3639/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2018-3639 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-3639 - OSV: https://osv.dev/vulnerability/CVE-2018-3639 --- From sbomify Insights: https://insights.sbomify.com/CVE-2018-3639/ Summaries are generated and may contain mistakes; the official description above is the record.