The ping_unhash function in net/ipv4/ping.c in the Linux kernel before 4.0.3 does not initialize a certain list data structure during an unhash operation, which allows local users to gain privileges or cause a denial of service (use-after-free and system crash) by leveraging the ability to make a SOCK_DGRAM socket system call for the IPPROTO_ICMP or IPPROTO_ICMPV6 protocol, and then making a connect system call after a disconnect.
CVE-2015-3636
MEDIUMCVSS v2 · 4.94.9—Elevated
EchelonGraph scoreLOW confidence
This CVE was only ever scored under CVSS v2.0. NVD CVSS v2.0 base 4.9 — v2 rates that MEDIUM (v2 bands: LOW 0.0–3.9 / MEDIUM 4.0–6.9 / HIGH 7.0–10.0; v2 has no CRITICAL band). Vector AV:L/AC:L/Au:N/C:N/I:N/A:C. CVSS v2 is an older, coarser metric than v3.1/v4.0 (no Scope, no User Interaction, no Attack Requirements), so it is not directly comparable to a v3 or v4 score. NVD has never re-scored this record under v3. EPSS predicts 2.5% exploitation probability in the next 30 days, which is reflected in EG Risk but does not lift the v2 base. Confidence: LOW.
Sources: epss, nvd_v2
4.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 2.5%CVSS v2: 4.9Exploit: Elevated riskExposed services: —
A fix is available — apply it.
Internet exposure
The internet-exposure footprint is temporarily unavailable — the KEV-Exposure radar's record for this CVE could not be loaded just now. That is not a finding of zero exposed services; please retry shortly.
- CVSS v2.0 (legacy)
- 4.9MEDIUMNVD never assigned a CVSS v3 rating to this CVE
- EG Score
- 4.9MEDIUMlow confidence
- EG Risk
- 43EG Risk 43/100CISA SSVC
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity49% × 45%Exploitation40% × 40%Automatability30% × 15%CISA SSVC: Track at low, Track or Track* at medium and Track* or Attend at high mission impact.Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 2.5%
- EPSS %ILE
- 83rd
- KEV
- Not listed
CISA SSVCTrack at low, Track or Track* at medium and Track* or Attend at high mission impact.
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation public PoC (EG-KEV: elevated) · Automatable unknown (not published for this CVE) · Technical impact unknown (not published for this CVE). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
August 6, 2015
Last Modified
May 6, 2026
References (56)
- cve@mitrehttp://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=a134f083e79fb4c3d0a925691e732c56911b4326
- cve@mitrehttp://lists.fedoraproject.org/pipermail/package-announce/2015-May/157788.html
- cve@mitrehttp://lists.fedoraproject.org/pipermail/package-announce/2015-May/157897.html
- cve@mitrehttp://lists.fedoraproject.org/pipermail/package-announce/2015-May/158804.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2015-07/msg00023.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2015-08/msg00011.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2015-09/msg00004.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2015-09/msg00007.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2015-09/msg00008.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2015-09/msg00009.html
- cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2015-09/msg00011.html
- cve@mitrehttp://rhn.redhat.com/errata/RHSA-2015-1221.html
- cve@mitrehttp://rhn.redhat.com/errata/RHSA-2015-1534.html
- cve@mitrehttp://rhn.redhat.com/errata/RHSA-2015-1564.html
- cve@mitrehttp://rhn.redhat.com/errata/RHSA-2015-1583.html
Vendor Advisories for CVE-2015-3636
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Frequently asked(4)
What is CVE-2015-3636?
CVE-2015-3636 is a medium vulnerability published on August 6, 2015. The pingunhash function in net/ipv4/ping.c in the Linux kernel before 4.0.3 does not initialize a certain list data structure during an unhash operation, which allows local users to gain privileges or cause a denial of service (use-after-free and system crash) by leveraging the ability to make a…
When was CVE-2015-3636 disclosed?
CVE-2015-3636 was first published on August 6, 2015, with the most recent update on May 6, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2015-3636 actively exploited?
CVE-2015-3636 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.5% probability of exploitation in the next 30 days (83rd percentile of EPSS-scored CVEs).
How do I remediate CVE-2015-3636?
A fix for CVE-2015-3636 is available: update to the fixed version the vendor names in its advisory.
Dependency Blast Radius
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