CVE-2024-3651: Denial of Service via Quadratic Complexity in kjd/idna
Noroxi assessment
Priority: Monitor (action score 30/100)
- Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
- Probability of exploitation in the next 30 days: 1.3% (FIRST EPSS); higher than 72.4% 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.
- Fixed version: Azure Linux 3.0 ARM 2.16.1-7, 24.0-2, 3.7-1; Azure Linux 3.0 x64 2.16.1-7, 24.0-2, 3.7-1; CBL Mariner 2.0 ARM 3.7-1.
Low priority for now. Upgrade to Azure Linux 3.0 ARM 2.16.1-7, 24.0-2, 3.7-1; Azure Linux 3.0 x64 2.16.1-7, 24.0-2, 3.7-1; CBL Mariner 2.0 ARM 3.7-1 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
A vulnerability was identified in the kjd/idna library, specifically within the `idna.encode()` function, affecting version 3.6. The issue arises from the function's handling of crafted input strings, which can lead to quadratic complexity and consequently, a denial of service condition. This vulnerability is triggered by a crafted input that causes the `idna.encode()` function to process the input with considerable computational load, significantly increasing the processing time in a quadratic manner relative to the input size.
- BDU:2024-04211
- GHSA-jjg7-2v4v-x38h
- ALSA-2024:3466
- ALSA-2024:3846
- ALSA-2024:4260
- DLA-3811-1
- openSUSE-SU-2024:13874-1
- openSUSE-SU-2026:11711-1
- PYSEC-2024-60
- RHSA-2024:3466
- RHSA-2024:3543
- RHSA-2024:3552
- RHSA-2024:3781
- RHSA-2024:3846
- RHSA-2024:4260
- RHSA-2024:8365
- RLSA-2024:3466
- RLSA-2024:3846
- RLSA-2024:4260
- SUSE-EL-9-CLIENT-TOOLS-2024-4029
- Published
- Jul 7, 2024
- Updated
- Jun 17, 2026
- EPSS
- 1.3% · 72th percentile
- CWE
- CWE-1333
Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.3%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 7.5
- CNA · @huntr_ai
- 6.2
- 1.3 point gap
CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
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.
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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 |
|---|---|---|
| kjd | internationalized domain names in applications | cpe:2.3:a:kjd:internationalized_domain_names_in_applications |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- kjd internationalized domain names in applications0.2 and later · before 3.7
Versions reported by the vendor
Affected version ranges reported by the assigning authority (@huntr_ai). Independent of NVD's CPE analysis and usually ahead of it.
kjd kjd/idna
- unspecified and later · before 3.7affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | python3-idna | before 2.5-7.el8_10 | 2.5-7.el8_10 |
| AlmaLinux:8 | python39 | before 3.9.19-1.module_el8.10.0+3849+a48d89aa | 3.9.19-1.module_el8.10.0+3849+a48d89aa |
| AlmaLinux:8 | python39-attrs | before 20.3.0-2.module_el8.6.0+2780+a40f65e1 | 20.3.0-2.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-cffi | before 1.14.3-2.module_el8.6.0+3248+c431e88c | 1.14.3-2.module_el8.6.0+3248+c431e88c |
| AlmaLinux:8 | python39-cffi | before 1.14.3-2.module_el8.6.0+2780+a40f65e1 | 1.14.3-2.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-chardet | before 3.0.4-19.module_el8.6.0+2780+a40f65e1 | 3.0.4-19.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-cryptography | before 3.3.1-3.module_el8.10.0+3765+2f9a457d | 3.3.1-3.module_el8.10.0+3765+2f9a457d |
| AlmaLinux:8 | python39-Cython | before 0.29.21-5.module_el8.6.0+3248+c431e88c | 0.29.21-5.module_el8.6.0+3248+c431e88c |
| AlmaLinux:8 | python39-Cython | before 0.29.21-5.module_el8.6.0+2780+a40f65e1 | 0.29.21-5.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-debug | before 3.9.19-1.module_el8.10.0+3849+a48d89aa | 3.9.19-1.module_el8.10.0+3849+a48d89aa |
| AlmaLinux:8 | python39-devel | before 3.9.19-1.module_el8.10.0+3849+a48d89aa | 3.9.19-1.module_el8.10.0+3849+a48d89aa |
| AlmaLinux:8 | python39-idle | before 3.9.19-1.module_el8.10.0+3849+a48d89aa | 3.9.19-1.module_el8.10.0+3849+a48d89aa |
| AlmaLinux:8 | python39-idna | before 2.10-4.module_el8.10.0+3849+a48d89aa | 2.10-4.module_el8.10.0+3849+a48d89aa |
| AlmaLinux:8 | python39-iniconfig | before 1.1.1-2.module_el8.6.0+2780+a40f65e1 | 1.1.1-2.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-libs | before 3.9.19-1.module_el8.10.0+3849+a48d89aa | 3.9.19-1.module_el8.10.0+3849+a48d89aa |
| AlmaLinux:8 | python39-lxml | before 4.6.5-1.module_el8.6.0+3248+c431e88c | 4.6.5-1.module_el8.6.0+3248+c431e88c |
| AlmaLinux:8 | python39-lxml | before 4.6.5-1.module_el8.6.0+2780+a40f65e1 | 4.6.5-1.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-mod_wsgi | before 4.7.1-7.module_el8.9.0+3634+fb2a896c | 4.7.1-7.module_el8.9.0+3634+fb2a896c |
| AlmaLinux:8 | python39-more-itertools | before 8.5.0-2.module_el8.6.0+2780+a40f65e1 | 8.5.0-2.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-numpy | before 1.19.4-3.module_el8.6.0+3248+c431e88c | 1.19.4-3.module_el8.6.0+3248+c431e88c |
| AlmaLinux:8 | python39-numpy | before 1.19.4-3.module_el8.6.0+2780+a40f65e1 | 1.19.4-3.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-numpy-doc | before 1.19.4-3.module_el8.6.0+2780+a40f65e1 | 1.19.4-3.module_el8.6.0+2780+a40f65e1 |
| AlmaLinux:8 | python39-numpy-f2py | before 1.19.4-3.module_el8.6.0+3248+c431e88c | 1.19.4-3.module_el8.6.0+3248+c431e88c |
| AlmaLinux:8 | python39-numpy-f2py | before 1.19.4-3.module_el8.6.0+2780+a40f65e1 | 1.19.4-3.module_el8.6.0+2780+a40f65e1 |
+96
Same product
kjd: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-45409Internationalized Domain Names in Applications (IDNA): Specially crafted inputs to idna.encode() can bypass CVE-2024-3651 fix27Monitor
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 |
|---|---|---|
| Azure Linux 3.0 ARM | 2.16.1-7 · tensorflow | Microsoft (MSRC) |
| Azure Linux 3.0 ARM | 24.0-2 · python-pip | Microsoft (MSRC) |
| Azure Linux 3.0 ARM | 3.7-1 · python-idna | Microsoft (MSRC) |
| Azure Linux 3.0 x64 | 2.16.1-7 · tensorflow | Microsoft (MSRC) |
| Azure Linux 3.0 x64 | 24.0-2 · python-pip | Microsoft (MSRC) |
| Azure Linux 3.0 x64 | 3.7-1 · python-idna | Microsoft (MSRC) |
| CBL Mariner 2.0 ARM | 3.7-1 · python-idna | Microsoft (MSRC) |
| CBL Mariner 2.0 x64 | 3.7-1 · python-idna | Microsoft (MSRC) |
| almalinux:python39 | 3.9.19-1.module_el8.10.0+3849+a48d89aa · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-attrs | 20.3.0-2.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-cffi | 1.14.3-2.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-chardet | 3.0.4-19.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-cryptography | 3.3.1-3.module_el8.10.0+3765+2f9a457d · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-Cython | 0.29.21-5.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-debug | 3.9.19-1.module_el8.10.0+3849+a48d89aa · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-devel | 3.9.19-1.module_el8.10.0+3849+a48d89aa · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-idle | 3.9.19-1.module_el8.10.0+3849+a48d89aa · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-idna | 2.10-4.module_el8.10.0+3849+a48d89aa · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-iniconfig | 1.1.1-2.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-PyMySQL | 0.10.1-2.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| alpine:py3-idna | 3.7-r0 · Alpine:v3.19 | Package registry (OSV) |
| debian:python-idna | 3.3-1+deb12u1 · Debian:12 | Package registry (OSV) |
| opensuse:python-idna | 2.6-150000.3.3.1 · openSUSE:Leap Micro 5.3 | Package registry (OSV) |
| PyPI:idna | 3.7 | Package registry (OSV) |
| red hat:mod_wsgi | 0:4.7.1-7.module+el8.9.0+19644+d68f775d · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:numpy | 0:1.19.4-3.module+el8.9.0+19644+d68f775d · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:numpy-debugsource | 0:1.19.4-3.module+el8.9.0+19644+d68f775d · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:python-cffi | 0:1.14.3-2.module+el8.9.0+19644+d68f775d · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:python-cffi-debugsource | 0:1.14.3-2.module+el8.9.0+19644+d68f775d · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:python-chardet | 0:3.0.4-19.module+el8.9.0+19644+d68f775d · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
+31
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.
| Source | Kind | Date |
|---|---|---|
| Proof-of-concept repository on GitHub | stars:0 | 2026-09-25 |
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.
- Published
- First PoC+809 d
- TodayNov 10, 2026+856 d
No history yet (it accumulates with the daily EPSS job).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
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.
- 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-1333 · Inefficient Regular Expression ComplexityCVSS 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.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (5 more)Show less
- lists.debian.org/debian-lts-announce/2024/05/msg00006.html
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4YQUPYH3SVZ5GFF2CDQ55FCM575AZTF2/
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/F2S5E23N6E52S46KGNYTDFB75LOC4N4D/
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/S5IDLLD2IKSIVRBSLB34WTSYGLMWUFWF/
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ULSC7HBJKXB3BZV367WM5BR6DFEC4Z43/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.