When handling a SSLv2-compatible ClientHello request, the server doesn't generate a new random value but sends an all-zero value instead.
Noroxi assessment
Priority: Monitor (action score 23/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 1.4% (FIRST EPSS); higher than 73.5% 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. Special conditions such as timing or configuration are required.
- Fixed version: nss (Alpine:v3.10) 3.39-r0; nss (Alpine:v3.8) 3.36.1-r1; nss (Debian:12) 2:3.39-1.
Low priority for now. Upgrade to nss (Alpine:v3.10) 3.39-r0; nss (Alpine:v3.8) 3.36.1-r1; nss (Debian:12) 2:3.39-1 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
When handling a SSLv2-compatible ClientHello request, the server doesn't generate a new random value but sends an all-zero value instead. This results in full malleability of the ClientHello for SSLv2 used for TLS 1.2 in all versions prior to NSS 3.39. This does not impact TLS 1.3.
- Published
- Apr 29, 2019
- Updated
- Jun 16, 2026
- EPSS
- 1.4% · 73th percentile
- CWE
- CWE-335
Report tools
Action score
23
Monitor
Low priority for now.
- CVSS
- 23 / 40 · 5.9 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.4%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
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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 helpAffected 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.
| Vendor | Product | CPE |
|---|---|---|
| mozilla | network security services | cpe:2.3:a:mozilla:network_security_services |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- mozilla network security servicesbefore 3.39
Versions reported by the vendor
Affected version ranges reported by the assigning authority (mozilla). Independent of NVD's CPE analysis and usually ahead of it.
NSS Network Security Services (NSS)
- All versions prior to NSS 3.39affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.10 | nss | before 3.39-r0 | 3.39-r0 |
| Alpine:v3.8 | nss | before 3.36.1-r1 | 3.36.1-r1 |
| Debian:12 | nss | before 2:3.39-1 | 2:3.39-1 |
| openSUSE:Tumbleweed | mozilla-nss | before 3.69.1-1.2 | 3.69.1-1.2 |
| Red Hat:enterprise_linux:6::client | nss | before 0:3.36.0-9.el6_10 | 0:3.36.0-9.el6_10 |
| Red Hat:enterprise_linux:6::client | nss-debuginfo | before 0:3.36.0-9.el6_10 | 0:3.36.0-9.el6_10 |
| Red Hat:enterprise_linux:6::client | nss-devel | before 0:3.36.0-9.el6_10 | 0:3.36.0-9.el6_10 |
| Red Hat:enterprise_linux:6::client | nss-pkcs11-devel | before 0:3.36.0-9.el6_10 | 0:3.36.0-9.el6_10 |
| Red Hat:enterprise_linux:6::client | nss-sysinit | before 0:3.36.0-9.el6_10 | 0:3.36.0-9.el6_10 |
| Red Hat:enterprise_linux:6::client | nss-tools | before 0:3.36.0-9.el6_10 | 0:3.36.0-9.el6_10 |
| Red Hat:enterprise_linux:7::client | nss | before 0:3.36.0-7.el7_5 | 0:3.36.0-7.el7_5 |
| Red Hat:enterprise_linux:7::client | nss-debuginfo | before 0:3.36.0-7.el7_5 | 0:3.36.0-7.el7_5 |
| Red Hat:enterprise_linux:7::client | nss-devel | before 0:3.36.0-7.el7_5 | 0:3.36.0-7.el7_5 |
| Red Hat:enterprise_linux:7::client | nss-pkcs11-devel | before 0:3.36.0-7.el7_5 | 0:3.36.0-7.el7_5 |
| Red Hat:enterprise_linux:7::client | nss-sysinit | before 0:3.36.0-7.el7_5 | 0:3.36.0-7.el7_5 |
| Red Hat:enterprise_linux:7::client | nss-tools | before 0:3.36.0-7.el7_5 | 0:3.36.0-7.el7_5 |
| SUSE:Linux Enterprise Module for Basesystem 15 | mozilla-nspr | before 4.20-3.3.2 | 4.20-3.3.2 |
| SUSE:Linux Enterprise Module for Basesystem 15 | mozilla-nss | before 3.40.1-3.7.2 | 3.40.1-3.7.2 |
| SUSE:Linux Enterprise Module for Desktop Applications 15 | MozillaFirefox | before 60.4.0-3.21.1 | 60.4.0-3.21.1 |
| SUSE:OpenStack Cloud 7 | mozilla-nspr | before 4.20-19.6.1 | 4.20-19.6.1 |
| SUSE:OpenStack Cloud 7 | mozilla-nss | before 3.40.1-58.18.1 | 3.40.1-58.18.1 |
| SUSE:OpenStack Cloud 7 | MozillaFirefox | before 60.4.0esr-109.55.1 | 60.4.0esr-109.55.1 |
Same product
mozilla: all recordsOther highest-scoring records for the same primary product.
- CVE-2017-5461Mozilla Network Security Services (NSS) before 3.21.4, 3.22.x through 3.28.x before 3.28.4, 3.29.x before 3.29.5, and 3.30.x before 3.30.1 a40Plan
- CVE-2009-2404Heap-based buffer overflow in a regular-expression parser in Mozilla Network Security Services (NSS) before 3.12.3, as used in Firefox, Thun38Monitor
- CVE-2018-12404A cached side channel attack during handshakes using RSA encryption could allow for the decryption of encrypted content.36Monitor
Published before and after this one in the same product
- ← EarlierCVE-2016-9574Jul 19, 2018 · nss before version 3.30 is vulnerable to a remote denial of service during the session handshake when using SessionTicket extension and ECDH23Monitor
- ← EarlierCVE-2016-8635Aug 1, 2018 · It was found that Diffie Hellman Client key exchange handling in NSS 3.21.x was vulnerable to small subgroup confinement attack.24Monitor
- Later →CVE-2020-25648Oct 20, 2020 · A flaw was found in the way NSS handled CCS (ChangeCipherSpec) messages in TLS 1.3.31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| alpine:nss | 3.39-r0 · Alpine:v3.10 | Package registry (OSV) |
| debian:nss | 2:3.39-1 · Debian:12 | Package registry (OSV) |
| opensuse:mozilla-nss | 3.69.1-1.2 · openSUSE:Tumbleweed | Package registry (OSV) |
| red hat:nss | 0:3.36.0-7.el7_5 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:nss-debuginfo | 0:3.36.0-7.el7_5 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:nss-devel | 0:3.36.0-7.el7_5 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:nss-pkcs11-devel | 0:3.36.0-7.el7_5 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:nss-sysinit | 0:3.36.0-7.el7_5 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:nss-tools | 0:3.36.0-7.el7_5 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| suse:mozilla-nspr | 4.20-3.3.2 · SUSE:Linux Enterprise Module for Basesystem 15 | Package registry (OSV) |
| suse:mozilla-nss | 3.40.1-3.7.2 · SUSE:Linux Enterprise Module for Basesystem 15 | Package registry (OSV) |
| suse:MozillaFirefox | 60.4.0-3.21.1 · SUSE:Linux Enterprise Module for Desktop Applications 15 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
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.
No dated events beyond publication.
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 researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
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).
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.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- none
- Availability
- none
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-335 · Incorrect Usage of Seeds in Pseudo-Random Number Generator (PRNG)CVSS vector
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
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
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (1 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.