CVE-2015-8803

The ecc_256_modp function in ecc-256.c in Nettle before 3.2 does not properly handle carry propagation and produces incorrect output in its implementation of the P-256 NIST elliptic curve, which allows attackers to have unspecified impact via unknown vectors, a different vulnerability than CVE-2015-8805.

Published: 2016-02-23 Last update: 2026-05-06 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2015-8803 is rated High Risk (74.4/100): CVSS Critical severity, with high exploitation likelihood (EPSS 12.34%, 94th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +2.48% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2015-8803

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-07-09 9.86% 12.34% +2.48%
2 2025-03-30 18.75% 9.86% -8.89%
3 2025-03-29 — 18.75% —

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2015-8803

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.0 CRITICAL
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2015-8803

OS Trackers for CVE-2015-8803

vendor priority summary link
debian not yet assigned CVE-2015-8803 not yet assigned priority: Debian including 1 source packages (nettle), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2015-8803
redhat medium — https://access.redhat.com/security/cve/CVE-2015-8803
suse medium CVE-2015-8803 severity moderate: SUSE including 79 source package names (2.78:libhogweed2-2.7.1-9.1, 2.78:libnettle4-2.7.1-9.1, …), 185 product×package rows across 67 product lines (Container caasp/v4/dnsmasq-nanny, Image SLES12-SP5-Azure-BYOS, … (67 product lines)): Fixed 185. https://www.suse.com/security/cve/CVE-2015-8803/
ubuntu medium CVE-2015-8803 medium priority: Ubuntu including 1 source packages (nettle), 8 status rows across 8 suites (precise, trusty, upstream, vivid, wily, xenial, yakkety, zesty): not-affected 4, released 3, ignored 1. https://ubuntu.com/security/CVE-2015-8803

Affected software / configurations for CVE-2015-8803

Vendor Product Version Raw CPE
nettle_project nettle <= 3.1.1 cpe:2.3:a:nettle_project:nettle:*:*:*:*:*:*:*:*
canonical ubuntu_linux 14.04 cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 15.10 cpe:2.3:o:canonical:ubuntu_linux:15.10:*:*:*:*:*:*:*
opensuse leap 42.1 cpe:2.3:o:opensuse:leap:42.1:*:*:*:*:*:*:*
opensuse opensuse 13.1 cpe:2.3:o:opensuse:opensuse:13.1:*:*:*:*:*:*:*
opensuse opensuse 13.2 cpe:2.3:o:opensuse:opensuse:13.2:*:*:*:*:*:*:*

References for CVE-2015-8803

URL Tags
http://lists.fedoraproject.org/pipermail/package-announce/2016-February/176807.html
http://lists.fedoraproject.org/pipermail/package-announce/2016-February/177229.html
http://lists.fedoraproject.org/pipermail/package-announce/2016-February/177473.html
http://lists.opensuse.org/opensuse-updates/2016-02/msg00091.html
http://lists.opensuse.org/opensuse-updates/2016-02/msg00093.html
http://lists.opensuse.org/opensuse-updates/2016-02/msg00100.html
http://rhn.redhat.com/errata/RHSA-2016-2582.html
http://www.openwall.com/lists/oss-security/2016/02/02/2
http://www.openwall.com/lists/oss-security/2016/02/03/1
http://www.ubuntu.com/usn/USN-2897-1
https://blog.fuzzing-project.org/38-Miscomputations-of-elliptic-curve-scalar-multiplications-in-Nettle.html
https://git.lysator.liu.se/nettle/nettle/commit/c71d2c9d20eeebb985e3872e4550137209e3ce4d Patch
https://lists.gnu.org/archive/html/info-gnu/2016-01/msg00006.html
https://lists.lysator.liu.se/pipermail/nettle-bugs/2015/003028.html Vendor Advisory
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