Trusting the Tool: Asymmetric Deference of LLM Vulnerability Auditors to Static-Analysis Evidence
Authors: ZhiHong Liu, Shuyao Gao
Organizations: Seoul School of Integrated Sciences and Technologies (aSSIST University), Seoul, Republic of Korea · Liaoning Mechanical & Electrical College of Technology, Dandong, Liaoning, China
Pipelines that combine large language models (LLMs) with static analysis let the model consume the analyser's output as evidence, but whether the model distinguishes true from false evidence, and whether its scrutiny depends on what the evidence claims, has not been measured. We built an intraprocedural analyser for C/C++ that produces proof obligations and audited vulnerable and patched functions from PrimeVul under six evidence conditions that differ only in the notes, including fabricated assurances that a missing check exists and fabricated alarms that an added check is missing. The study covers 916 pairs in four disjoint sets, eleven model configurations from four vendors and 16,572 audits; no model is trained or fine-tuned. True evidence barely improved accuracy (+0.02). False evidence acted asymmetrically: relative to true notes about the same operations, false assurances lowered the detection of real vulnerabilities by up to 19 points, whereas false alarms never significantly lowered accuracy and were disputed far more often. An internally registered replication on seven new models confirmed that false assurances move verdicts towards their claim more than false alarms do (mean asymmetry +0.16, 95% CI +0.10 to +0.24). Instructions in the audit prompt did not reliably reduce deference; the best one failed to replicate. Verifying each claim in a separate call and showing the refuted claims raised accuracy under false assurances by 12 points in a pre-specified test (p=0.002) without loss under true evidence; for a second model the gain was smaller and not significant. Pipelines should therefore verify a tool's guarantees before the model relies on them, and studies should measure deference in a direction-aware way.
Figures & tables
Figure 1: Study overview. For each PrimeVul pair, an intraprocedural analyser produces proof obligations for both versions; the fix commit decides which obligations are relevant and how false evidence is built. The same function is audited under every evidence condition and, for RQ4, under different presentations of the same notes.
Evidence
Content
Functions
C0
none
plain audit
374
C1
all, true
every obligation the analyser reports
374
C2
relevant, true
only patch-relevant obligations
189
C3
irrelevant, true
only obligations away from the patch that carry a concern
183
C4
false assurance
vulnerable versions: relevant concerns replaced by fabricated, refutable guarantees
83
C5
false alarm
patched versions: concerns the patch removed, guards deleted
97
Table 1: Evidence conditions. Functions: number of study-set functions to which a condition applies.
Name in this paper
API model identifier
R
Vendor
Sets (conditions)
deepseek-chat
deepseek-chat
DeepSeek
S (all); H, D (C1, C2, C4, C5); T (C2, C4)
deepseek-flash (R)
deepseek-flash
✓
DeepSeek
S (all)
deepseek-v4-pro (R)
deepseek-v4-pro
✓
DeepSeek
S, 60 pairs (C0, C2, C4, C5)
qwen-plus
qwen-plus-2025-12-01
Alibaba
S (C2, C4, C5); T (C2, C4)
Registered replication (H3), via Alibaba Cloud Bailian
glm-5.2
glm-5.2
Zhipu AI
S (C2, C4, C5)
Table 2: Model configurations. R: reasoning enabled (effort low ). Sets: S study, H held-out, D development, T test. Conditions in brackets were run on a subset only.
Figure 3: Order of the RQ4 evaluations. After the strategy selected on the study set failed to replicate, strategies were compared on a separate development set only, and the frozen strategy was tested once on unseen pairs with pre-specified hypotheses. Values are accuracy changes under false assurances relative to the plain presentation (uncorrected McNemar p ).
Figure 4: Accuracy per evidence condition on the study set, for vulnerable versions (left) and patched versions (right). Conditions apply to different subsets of functions ( Table 1 ), so the figure is descriptive; paired comparisons are in Fig. 5 . False evidence exists only for one version: false assurances ( C4 ) for vulnerable versions and false alarms ( C5 ) for patched ones.
Figure 5: Effect of false evidence relative to true evidence about the same operations, with 95% bootstrap CIs. Orange: false assurance on vulnerable versions ( C4 − C2 ); blue: false alarm on patched versions ( C5 − C2 ). The upper block shows the four exploratory configurations and the lower block the seven models of the registered replication ( Section 6.4 ). * p<.05 , ** p<.01 (exact McNemar). † 60-pair subset.
Model
Contrast
n
True → false
Discordant
p
Difference (95% CI)
deepseek-chat
C4 vs C2
83
0.75 → 0.64
10 / 1
0.012
−0.11 ( −0.18 , −0.04 )
C5 vs C2
67
0.67 → 0.79
0 / 8
0.008
+0.12 ( +0.04 , +0.19 )
deepseek-flash (R)
C4 vs C2
83
0.87 → 0.90
3 / 6
0.508
+0.04 ( −0.04 , +0.11 )
C5 vs C2
67
0.37 → 0.55
3 / 15
0.008
+0.18 ( +0.06 , +0.30 )
deepseek-v4-pro (R) †
C4 vs C2
29
0.97 → 0.83
4 / 0
0.125
−0.14 ( −0.28 , −0.03 )
C5 vs C2
28
0.29 → 0.32
4 / 3
1.000
+0.04 ( −0.14 , +0.21 )
Table 3: Matched contrasts on the study set. n : functions with both conditions. Discordant: functions correct only under the true notes / only under the false notes.
Claims
n
Refuted
Confirmed
Unclear
C4 false assurances
251
0.76 (0.70, 0.81)
0.10
0.14
C5 false alarms
428
0.79 (0.75, 0.82)
0.06
0.15
C2 true holds-here
203
0.02 (0.01, 0.06)
0.90
0.08
C2 true concerns
488
0.45 (0.41, 0.50)
0.31
0.24
Table 4: Verification of true and false claims when the model is asked to check them ( deepseek-chat , study set). Shares of claims; refuted with Wilson 95% CI.
Figure 6: (a) Share of answers that dispute a note according to the lexical cue, by model and type of false evidence (Wilson 95% CIs). (b) Share of answers that reject the false note according to each annotator, reweighted from the 80-answer stratified sample to all C4 / C5 answers (bootstrap 95% CIs).
Figure 7: How far false evidence moves verdicts towards its own claim, relative to true notes about the same operations (left), and the asymmetry between false assurances and false alarms (right), with 95% bootstrap CIs over pairs. Top: the four configurations from which the measure was derived; bottom: the seven models of the registered replication. Diamonds: mean over the models of a group. † 60-pair subset.
Strategy
Dimension
Change relative to plain
quote
framing
instruction to treat notes as unverified claims and to quote the code before relying on one
alarms
content
“holds here” assurances removed; operations and concerns kept
reframe
framing
assurances recast as claims to verify (“to verify: the tool reports …”)
provenance
source
the source text of every line a note cites is printed next to the citation
verify
checking
a separate call checks each claim against the code; refuted claims are withheld
verify-show
checking
as verify, but refuted claims are listed separately as contradicted by the code
Table 5: Presentation strategies. All use the same notes; only their presentation changes.
Figure 8: Verify-show on a false assurance (illustrative, simplified from a study-set pair). A first call checks each claim of the notes against the code and quotes the deciding line; the audit then sees the confirmed notes and, separately, the claims that the code contradicts.
Figure 9: Every presentation strategy evaluated, in the order of evaluation: accuracy change relative to the plain presentation on vulnerable versions under false assurances (left) and under true relevant evidence (right). Hollow markers: exploratory comparisons; filled markers: the pre-specified test, run once. Blue: deepseek-chat ; pink: qwen-plus .
Large language model auditing tests models and deployed systems for bias, safety, privacy, reliability, and provenance using behavioral and internal evidence.