Skip to content
Noroxi
CVE-2020-1967· NVD / CVE Program· CNA openssl

Segmentation fault in SSL_check_chain

Noroxi assessment

Priority: Plan (action score 46/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 53.3% (FIRST EPSS); higher than 98.9% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: openssl (Alpine:v3.10) 1.1.1g-r0; openssl3 (Alpine:v3.15) 1.1.1g-r0; openssl-src (crates.io) 111.9.0.
  • Mentioned 3 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Add it to your regular patch cycle. Upgrade to openssl (Alpine:v3.10) 1.1.1g-r0; openssl3 (Alpine:v3.15) 1.1.1g-r0; openssl-src (crates.io) 111.9.0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due to a NULL pointer dereference as a result of incorrect handling of the "signature_algorithms_cert" TLS extension. The crash occurs if an invalid or unrecognised signature algorithm is received from the peer. This could be exploited by a malicious peer in a Denial of Service attack. OpenSSL version 1.1.1d, 1.1.1e, and 1.1.1f are affected by this issue. This issue did not affect OpenSSL versions prior to 1.1.1d. Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f).

HighCVSS 7.5 · v3.1—Proof of concept Fix available
Published
Apr 21, 2020
Updated
Oct 8, 2026
EPSS
53.3% · 98th percentile

Report tools

JSON

Action score

46

Plan

Add it to your regular patch cycle.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
16 / 30 · 53.3%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2020-1967

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for openssl records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
opensslopenssl
debiandebian linux
freebsdfreebsd
fedoraprojectfedora
oracleapplication server
oracleenterprise manager base platform
oracleenterprise manager for storage management
oracleenterprise manager ops center
oraclehttp server
oraclejd edwards world security
oraclemysql
oraclemysql connectors

and 14 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • broadcom fabric operating systemall versions
  • debian debian linux10.0
  • debian debian linux9.0
  • fedoraproject fedora30
  • fedoraproject fedora31
  • fedoraproject fedora32
  • freebsd freebsd12.1
  • jdedwards enterpriseonebefore 9.2.5.0
  • netapp active iq unified manager9.5 and later
  • netapp active iq unified manager7.3 and later
  • netapp e-series performance analyzerall versions
  • netapp oncommand insightall versions
  • netapp oncommand workflow automationall versions
  • netapp smi-s providerall versions
  • netapp snapcenterall versions
  • netapp steelstore cloud integrated storageall versions
  • openssl openssl1.1.1d and later · up to 1.1.1f inclusive
  • opensuse leap15.1
  • opensuse leap15.2
  • oracle application server12.1.3

Versions reported by the vendor

Affected version ranges reported by the assigning authority (openssl). Independent of NVD's CPE analysis and usually ahead of it.

  • OpenSSL OpenSSL

    • Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f)affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.10opensslfrom 1.1.1d · before 1.1.1g-r01.1.1g-r0
Alpine:v3.15openssl3before 1.1.1g-r01.1.1g-r0
crates.ioopenssl-srcfrom 111.6.0 · before 111.9.0111.9.0
Debian:10opensslbefore 1.1.1d-0+deb10u31.1.1d-0+deb10u3
Debian:12opensslbefore 1.1.1g-11.1.1g-1
openSUSE:Leap 15.1rustbefore 1.43.1-lp151.5.13.11.43.1-lp151.5.13.1
openSUSE:Leap 15.1rust-cbindgenbefore 0.14.1-lp151.8.20.14.1-lp151.8.2
openSUSE:Leap 15.2rustbefore 1.43.1-lp152.3.5.11.43.1-lp152.3.5.1
openSUSE:Leap 15.2rust-cbindgenbefore 0.14.1-lp152.2.4.10.14.1-lp152.2.4.1
openSUSE:Tumbleweedrust1.53before 1.53.0-2.51.53.0-2.5
SUSE:Linux Enterprise Module for Development Tools 15 SP1rustbefore 1.43.1-12.11.43.1-12.1
SUSE:Linux Enterprise Software Development Kit 12 SP4openssl-1_1before 1.1.1d-2.23.11.1.1d-2.23.1

Same product

openssl: all records

Other highest-scoring records for the same primary product.

  • CVE-2014-0160The (1) TLS and (2) DTLS implementations in OpenSSL 1.0.1 before 1.0.1g do not properly handle Heartbeat Extension packets, which allows remKEV
    90Now
  • CVE-2021-3711SM2 Decryption Buffer Overflow
    65This week
  • CVE-2003-0545Double free vulnerability in OpenSSL 0.9.7 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code
    65This week
  • CVE-2016-2108The ASN.1 implementation in OpenSSL before 1.0.1o and 1.0.2 before 1.0.2c allows remote attackers to execute arbitrary code or cause a denia
    62This week
  • CVE-2016-6309statem/statem.c in OpenSSL 1.1.0a does not consider memory-block movement after a realloc call, which allows remote attackers to cause a den
    60This week
  • CVE-2022-3786X.509 Email Address Variable Length Buffer Overflow
    58Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
alpine:openssl1.1.1g-r0 · Alpine:v3.10Package registry (OSV)
alpine:openssl31.1.1g-r0 · Alpine:v3.15Package registry (OSV)
crates.io:openssl-src111.9.0Package registry (OSV)
debian:openssl1.1.1g-1 · Debian:12Package registry (OSV)
opensuse:rust1.43.1-lp151.5.13.1 · openSUSE:Leap 15.1Package registry (OSV)
opensuse:rust-cbindgen0.14.1-lp151.8.2 · openSUSE:Leap 15.1Package registry (OSV)
opensuse:rust1.531.53.0-2.5 · openSUSE:TumbleweedPackage registry (OSV)
suse:openssl-1_11.1.1d-2.23.1 · SUSE:Linux Enterprise Software Development Kit 12 SP4Package registry (OSV)
suse:rust1.43.1-12.1 · SUSE:Linux Enterprise Module for Development Tools 15 SP1Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:202020-04-28

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+6 d
  3. TodayOct 16, 2026+2369 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-476 · NULL Pointer Dereference

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (19 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records