Heap-based buffer overflow in the ALGnew function in block_templace.c in Python Cryptography Toolkit (aka pycrypto) allows remote attackers
Heap-based buffer overflow in the ALGnew function in block_templace.c in Python Cryptography Toolkit (aka pycrypto) allows remote attackers to execute arbitrary code as demonstrated by a crafted iv parameter to cryptmsg.py.
- Published
- Feb 15, 2017
- Updated
- Jun 16, 2026
- EPSS
- 9.6% · 95th percentile
- CWE
- CWE-119
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Report tools
Action score
42
Plan
Add it to your regular patch cycle.
- CVSS
- 39 / 40 · 9.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 3 / 30 · 9.6%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| dlitz | pycrypto | cpe:2.3:a:dlitz:pycrypto |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- dlitz pycryptoup to 2.6.1 inclusive
- fedoraproject fedora24
- fedoraproject fedora25
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:7 | python-crypto | before 2.6-4+deb7u4 | 2.6-4+deb7u4 |
| PyPI | pycrypto | all versions | — |
| PyPI | pycrypto | up to and including 2.6.1 | — |
| SUSE:Linux Enterprise Module for Public Cloud 12 | python-paramiko | before 1.15.2-2.6.1 | 1.15.2-2.6.1 |
| SUSE:Linux Enterprise Server 11 SP3-CLIENT-TOOLS | python-pycrypto | before 2.6.1-5.1 | 2.6.1-5.1 |
| SUSE:OpenStack Cloud 6 | python-paramiko | before 1.15.2-2.3.1 | 1.15.2-2.3.1 |
| SUSE:OpenStack Cloud 6 | python-pycrypto | before 2.6.1-10.3.1 | 2.6.1-10.3.1 |
Same product
dlitz: all recordsOther highest-scoring records for the same primary product.
- CVE-2018-6594lib/Crypto/PublicKey/ElGamal.py in PyCrypto through 2.6.1 generates weak ElGamal key parameters, which allows attackers to obtain sensitive 31Monitor
- CVE-2013-1445The Crypto.Random.atfork function in PyCrypto before 2.6.1 does not properly reseed the pseudo-random number generator (PRNG) before allowin18Monitor
- CVE-2012-2417PyCrypto before 2.6 does not produce appropriate prime numbers when using an ElGamal scheme to generate a key, which reduces the signature s18Monitor
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:python-crypto | 2.6-4+deb7u4 · Debian:7 | Package registry (OSV) |
| suse:python-paramiko | 1.15.2-2.3.1 · SUSE:OpenStack Cloud 6 | Package registry (OSV) |
| suse:python-pycrypto | 2.6.1-5.1 · SUSE:Linux Enterprise Server 11 SP3-CLIENT-TOOLS | 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.
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
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-119 · Improper Restriction of Operations within the Bounds of a Memory BufferCVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Overflow BuffersCAPEC-100likelihood: High · Very High
- Buffer ManipulationCAPEC-123likelihood: High · Very High
- Client-side Injection-induced Buffer OverflowCAPEC-14likelihood: Medium · High
- Filter Failure through Buffer OverflowCAPEC-24likelihood: High · High
- MIME ConversionCAPEC-42likelihood: High · High
- Overflow Binary Resource FileCAPEC-44likelihood: High · Very High
- Buffer Overflow via Symbolic LinksCAPEC-45likelihood: High · High
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✗ → ✓
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References
- www.openwall.com/lists/oss-security/2016/12/27/8
- www.securityfocus.com/bid/95122
- bugzilla.redhat.com/show_bug.cgi?id=1409754
- github.com/dlitz/pycrypto/commit/8dbe0dc3eea5c689d4f76b37b93fe216cf1f00d4
- github.com/dlitz/pycrypto/issues/176
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/C6BWNADPLKDBBQBUT3P75W7HAJCE7M3B/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RJ37R2YLX56YZABFNAOWV4VTHTGYREAE/
- security.gentoo.org/glsa/201702-14
Vendor advisories and official records. Exploit/PoC links are deliberately left out.