A Bleichenbacher type side-channel based padding oracle attack was found in the way nettle handles endian conversion of RSA decrypted PKCS#1
A Bleichenbacher type side-channel based padding oracle attack was found in the way nettle handles endian conversion of RSA decrypted PKCS#1 v1.5 data. An attacker who is able to run a process on the same physical core as the victim process, could use this flaw extract plaintext or in some cases downgrade any TLS connections to a vulnerable server.
- Published
- Dec 3, 2018
- Updated
- Jun 16, 2026
- EPSS
- 1.5% · 73th percentile
- CWE
- CWE-203
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
22
Monitor
Low priority for now.
- CVSS
- 22 / 40 · 5.7 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.5%
CNA vs NVD score
- NVD
- 5.7
- CNA · redhat
- 4.7
- 1.0 point gap
CVSS:3.0/AV:P/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| nettle project | nettle | cpe:2.3:a:nettle_project:nettle |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- nettle project nettleup to 3.4 inclusive
Versions reported by the vendor
Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.
[UNKNOWN] nettle
- n/aaffected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | nettle | before 3.4.1~rc1-1 | 3.4.1~rc1-1 |
| SUSE:Linux Enterprise Module for Basesystem 15 | libnettle | before 3.4-4.3.1 | 3.4-4.3.1 |
Same product
nettle project: all recordsOther highest-scoring records for the same primary product.
- CVE-2015-8805The ecc_256_modq function in ecc-256.c in Nettle before 3.2 does not properly handle carry propagation and produces incorrect output in its 40Plan
- CVE-2015-8804x86_64/ecc-384-modp.asm in Nettle before 3.2 does not properly handle carry propagation and produces incorrect output in its implementation 40Plan
- CVE-2015-8803The 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 40Plan
- CVE-2023-36660The OCB feature in libnettle in Nettle 3.9 before 3.9.1 allows memory corruption.39Monitor
- CVE-2021-20305A flaw was found in Nettle in versions before 3.7.2, where several Nettle signature verification functions (GOST DSA, EDDSA & ECDSA) result 33Monitor
- CVE-2021-3580A flaw was found in the way nettle's RSA decryption functions handled specially crafted ciphertext.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 |
|---|---|---|
| debian:nettle | 3.4.1~rc1-1 · Debian:12 | Package registry (OSV) |
| suse:libnettle | 3.4-4.3.1 · SUSE:Linux Enterprise Module for Basesystem 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
- Physical access to the device is required.
- 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
- low · data or configuration can be modified
- Availability
- none
Impact can extend beyond the vulnerable component (scope changes).
- Attack vector
- Physical
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality impact
- High
- Integrity impact
- Low
- Availability impact
- None
Weakness class (CWE)
CWE-203 · Observable DiscrepancyCVSS vector
CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:C/C:H/I:L/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.
Attack patterns (CAPEC)
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.